An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).
CVE-2021-3449
“▲” beside the score: it is higher than NVD's CVSS score.
Score elevated to 7.8 because EPSS predicted 64% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. NVD baseline CVSS 5.9 retained for reference. Confidence: see factors.
Also known asEUVD-2021-1628 (ENISA EUVD) · GHSA-83mx-573x-5rw9 (GitHub Security Advisories) · RUSTSEC-2021-0055 (OSV.dev)Source: ENISA EUVD
- High exploitation likelihood — EPSS 64%
- Public exploit or proof-of-concept code is available
A fix is available — apply it.
- CVSS v3
- 5.9
- EG Score
- 7.8HIGHhigh confidence
- EG Risk
- 67EG Risk 67/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity59% × 45%Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation64% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 64%
- EPSS %ILE
- 99th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 5.9 MEDIUM): a likelihood of exploitation, not impact.
- EG Severity
- 5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 64% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
March 25, 2021
Last Modified
October 8, 2026
Advisory Details (7)
Auto-updated Oct 8, 2026[SECURITY] [DLA 2751-1] postgresql-9.6 security update
https://lists.debian.org/debian-lts-announce/2021/08/msg00029.htmloss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing
http://www.openwall.com/lists/oss-security/2021/03/28/4oss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing
http://www.openwall.com/lists/oss-security/2021/03/28/3oss-security - Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing
http://www.openwall.com/lists/oss-security/2021/03/27/2oss-security - OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing
http://www.openwall.com/lists/oss-security/2021/03/27/1Vendor Advisories for CVE-2021-3449(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(12)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libecpg-compat3 (13.4-0ubuntu0.21.04.1) @ hirsute | 2026-10-29 | ubuntu |
| ubuntu | openssl (1.1.1f-1ubuntu4.3) @ groovy | 2026-10-29 | ubuntu |
| redhat | jws5-tomcat-native-0:1.2.25-4.redhat_4.el8jws | 2021-04-14 | redhat |
| redhat | patch | 2021-04-14 | redhat |
| redhat | tomcat-native-0:1.2.23-24.redhat_24.ep7.el7 | 2021-04-14 | redhat |
| redhat | jbcs-httpd24-openssl-pkcs11-0:0.4.10-20.jbcs.el7 | 2021-04-14 | redhat |
| redhat | redhat-virtualization-host-0:4.4.5-20210330.0.el8_3 | 2021-04-14 | redhat |
| redhat | openssl | 2021-04-14 | redhat |
| redhat | openssl-1:1.1.1c-5.el8_1 | 2021-04-07 | redhat |
| redhat | openssl-1:1.1.1c-18.el8_2 | 2021-04-05 | redhat |
| redhat | openssl-1:1.1.1g-15.el8_3 | 2021-03-30 | redhat |
| rust | openssl-src @ 111.15.0 (fixes < 111.15.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(24 across 22 ecosystems)
Alpine:v3.15(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
| openssl3 | — |
| — |
Alpine:v3.16(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
| openssl3 | — |
| — |
Alpine:v3.10(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.17(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.18(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.19(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.20(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Alpine:v3.9(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
crates.io(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl-src | — |
| — |
Debian:10(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | 1.1.1c-1 ... 1.1.1d-0+deb10u5 (6 versions) |
| — |
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| openssl | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(12)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
- Red HatRHSA-2021:1024IMPORTANT2021-03-25
RHSA-2021:1024 — Important
- Red HatRHSA-2021:1063IMPORTANT2021-03-25
RHSA-2021:1063 — Important
- Red HatRHSA-2021:1131IMPORTANT2021-03-25
RHSA-2021:1131 — Important
- Red HatRHSA-2021:1189IMPORTANT2021-03-25
RHSA-2021:1189 — Important
- Red HatRHSA-2021:1195IMPORTANT2021-03-25
RHSA-2021:1195 — Important
- Red HatRHSA-2021:1196IMPORTANT2021-03-25
RHSA-2021:1196 — Important
- Red HatRHSA-2021:1199IMPORTANT2021-03-25
RHSA-2021:1199 — Important
- Red HatRHSA-2021:1200IMPORTANT2021-03-25
RHSA-2021:1200 — Important
- Red HatRHSA-2021:1202IMPORTANT2021-03-25
RHSA-2021:1202 — Important
- Red HatRHSA-2021:1203IMPORTANT2021-03-25
RHSA-2021:1203 — Important
- UbuntuUSN-4891-1HIGH
OpenSSL vulnerability
- UbuntuUSN-5038-1HIGH
PostgreSQL vulnerabilities
Data Freshness Timeline
(refreshed 10× in last 7d / 35× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 94 of 164 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 70 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 08:32 UTCGHSA enrichmentGHSA-83mx-573x-5rw9 · GitHub severity MODERATE · GitHub CVSS 5.9
- 2026-11-01 08:32 UTCEG score recompute
- 2026-10-31 16:29 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-30 16:30 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-29 16:29 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-29 06:53 UTCEG score recompute
- 2026-10-29 06:53 UTCVendor advisory
- 2026-10-29 03:55 UTCOSV refresh
- 2026-10-28 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-27 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-25 18:26 UTCEG score recompute
- 2026-10-25 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-24 16:29 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-21 09:27 UTCEG score recompute
- 2026-10-21 09:27 UTCVendor advisory
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-18 08:59 UTCEG score recompute
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-16 16:34 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-14 16:29 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-13 16:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-12 19:15 UTCEG score recompute
Show 69 moreShow fewer
- 2026-10-12 16:30 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-11 23:40 UTCEG score recompute
- 2026-10-11 13:44 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-08 22:28 UTCVendor advisory
- 2026-10-08 21:33 UTCEG score recompute
- 2026-10-08 21:33 UTCVendor advisory
- 2026-10-07 23:45 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-02 16:23 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-10-01 19:46 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-30 15:37 UTCEG score recompute
- 2026-09-30 15:00 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-28 13:47 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-27 13:41 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-26 15:54 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-26 05:55 UTCOSV refresh
- 2026-09-24 14:00 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-23 13:44 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-22 14:44 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-21 20:28 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-20 20:13 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-18 19:23 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-17 19:23 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-16 14:05 UTCEPSS rescoreEPSS 64% · 99th percentile
- 2026-09-15 03:06 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-12 14:57 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-11 09:33 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-08 21:56 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-06 20:31 UTCOSV refresh
- 2026-09-06 13:45 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-05 15:25 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-04 13:57 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-02 14:09 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-01 13:50 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-09-01 03:33 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-30 19:14 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-28 21:37 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-27 14:22 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-26 14:43 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-25 13:46 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-24 14:13 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-21 23:46 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-20 22:52 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-20 06:34 UTCOSV refresh
- 2026-08-19 17:01 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-18 13:45 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-17 13:44 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-16 14:53 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-16 02:11 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-15 01:27 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-13 21:57 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-12 13:48 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-11 13:38 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-07 16:24 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-05 19:14 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-08-05 01:40 UTCOSV refresh
- 2026-07-30 16:25 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-30 01:28 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-28 15:33 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-26 14:52 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-25 14:15 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-24 14:15 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-23 14:16 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-23 02:01 UTCEG score recompute▲ 1.90
- 2026-07-22 22:48 UTCEG score recompute
- 2026-07-22 14:06 UTCEPSS rescoreEPSS 63% · 99th percentile
- 2026-07-21 15:22 UTCEPSS rescoreEPSS 63% · 99th percentile
Publicly available exploits
(1 reference)Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.
- GitHub PoCriptl/cve-2021-3449Published Mar 26, 2021
CVE-2021-3449 OpenSSL denial-of-service exploit 👨🏻💻
Open source ↗
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownAlpine:v3.10:openssl
- CVE-2021-23840NVD 7.5EG 8.1EPSS p99HIGH
- CVE-2020-1967NVD 7.5EG 8.1EPSS p99HIGH
- CVE-2021-23841EG 5.9EPSS p94MEDIUM
- CVE-2020-1971EG 5.9EPSS p94MEDIUM
- CVE-2019-1551EG 5.3EPSS p97MEDIUM
- CVE-2019-1547EG 4.7MEDIUM
- CVE-2019-1563EG 3.7EPSS p90LOW
- CVE-2021-3450EG 7.4EPSS p97HIGH
- CVE-2019-1543EG 7.4EPSS p93HIGH
- CVE-2018-0734EG 5.9EPSS p96MEDIUM
Same vendor
2 shownredhat:RHSA-2021:1024 · ubuntu:USN-5038-1
Frequently asked(5)
What is CVE-2021-3449?
When was CVE-2021-3449 made public?
Is CVE-2021-3449 actively exploited?
What is the CVSS score of CVE-2021-3449?
How do I remediate CVE-2021-3449?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3449
Is Your Infrastructure Affected by CVE-2021-3449?
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