Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
CVE-2026-63382
“—” beside the score: it is equal to the CVSS score beside it.
This critical-severity CVE scores 9.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (56th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-63505 (ENISA EUVD)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 9.2
- EG Score
- 9.2CRITICALmedium confidence
- EG Risk
- 72EG Risk 72/100
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)Severity92% × 45%Impact severity (EG Severity): CVSS 9.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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
- 0.8%
- EPSS %ILE
- 56th
- 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 (9.2): severity, escalated by confirmed exploitation. This CVE's 9.2 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.2 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 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, Track* at medium and Attend at high mission impact.
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 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 total (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
August 20, 2026
Last Modified
October 26, 2026
Advisory Details (7)
Auto-updated Sep 15, 2026libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling · Advisory · libevent/libevent · GitHub
https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8jLibevent 2.2.2-alpha
Patch available: libevent/libevent release-2.2.2-alpha
https://github.com/libevent/libevent/releases/tag/release-2.2.2-alphaLibevent 2.1.13-stable
Patch available: libevent/libevent release-2.1.13-stable
https://github.com/libevent/libevent/releases/tag/release-2.1.13-stablecommit ac38703b2d31 (libevent/libevent)
Patch available: libevent/libevent release-2.1.13-stable (contains commit ac38703b2d31)
https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0commit 83ba67373032 (libevent/libevent)
Patch available: libevent/libevent release-2.2.2-alpha (contains commit 83ba67373032)
https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660commit 5119ceb00557 (libevent/libevent)
Patch available: libevent/libevent release-2.2.2-alpha (contains commit 5119ceb00557)
https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6ecommit 10abb34b8dc3 (libevent/libevent)
Patch available: libevent/libevent release-2.1.13-stable (contains commit 10abb34b8dc3)
https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6Vendor Advisories for CVE-2026-63382(12)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:89197Red Hat Product SecurityCritical
Red Hat Security Advisory: OpenShift Container Platform 4.22.20 bug fix and security update
- RHSA-2026:72476Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:72475Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:72470Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:72399Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:72395Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:72394Red Hat Product SecurityHigh
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
- RHSA-2026:71603Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 security update
- +4 more
Patch Availability(13)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libevent-pthreads-2.0-5 (2.0.21-stable-2ubuntu0.16.04.1+esm1) @ xenial | 2026-11-02 | ubuntu |
| redhat | openshift/ose-rhel-coreos-9:4.22.9.8.202610241758-0 | 2026-10-27 | redhat |
| redhat | cert-manager/cert-manager-operator-rhel9:1790272426 | 2026-09-28 | redhat |
| redhat | cert-manager/jetstack-cert-manager-rhel9:1790223279 | 2026-09-28 | redhat |
| redhat | cert-manager/cert-manager-operator-rhel9:1790589855 | 2026-09-28 | redhat |
| redhat | cert-manager/jetstack-cert-manager-rhel9:1790589912 | 2026-09-28 | redhat |
| redhat | cert-manager/cert-manager-istio-csr-rhel9:1790589914 | 2026-09-28 | redhat |
| redhat | cert-manager/cert-manager-istio-csr-rhel9:1790223719 | 2026-09-28 | redhat |
| redhat | rhui5/rhua-rhel9:1790242004 | 2026-09-24 | redhat |
| redhat | libevent-0:2.1.8-11.el8_10 | 2026-09-16 | redhat |
| redhat | libevent-0:2.1.13-1.el10_2 | 2026-09-16 | redhat |
| redhat | libevent-0:2.1.13-1.el9_8 | 2026-09-16 | redhat |
| redhat | libevent-main-2.1.13-0.1.hum1 | 2026-09-03 | redhat |
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
(3 across 3 ecosystems)
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| libevent | 2.1.12-stable-8 |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| libevent | 2.1.12-stable-10 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| libevent | 2.1.12-stable-10, 2.1.13-stable-1~deb13u1 |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
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.
Data Freshness Timeline
(refreshed 21× in last 7d / 107× 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 99 of 337 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 238 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 06:57 UTCEG score recompute
- 2026-11-02 06:57 UTCVendor advisory
- 2026-11-01 08:00 UTCEG score recompute
- 2026-11-01 08:00 UTCVendor advisory
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
- 2026-10-31 09:03 UTCEG score recompute
- 2026-10-31 09:03 UTCVendor advisory
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
- 2026-10-30 10:06 UTCEG score recompute
- 2026-10-30 10:06 UTCVendor advisory
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-29 11:07 UTCEG score recompute
- 2026-10-29 11:07 UTCVendor advisory
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-28 12:02 UTCEG score recompute
- 2026-10-28 12:02 UTCVendor advisory
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-27 13:05 UTCVendor advisory
- 2026-10-27 09:27 UTCEG score recompute
- 2026-10-27 09:27 UTCVendor advisory
- 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-26 10:26 UTCVendor advisory
- 2026-10-26 00:41 UTCEG score recompute
- 2026-10-26 00:41 UTCVendor advisory
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
Show 74 moreShow fewer
- 2026-10-25 14:13 UTCEG score recompute
- 2026-10-25 01:41 UTCEG score recompute
- 2026-10-25 01:41 UTCVendor advisory
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-24 02:43 UTCEG score recompute
- 2026-10-24 02:43 UTCVendor advisory
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-23 03:45 UTCEG score recompute
- 2026-10-23 03:45 UTCVendor advisory
- 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-22 04:44 UTCEG score recompute
- 2026-10-22 04:44 UTCVendor advisory
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-21 05:45 UTCEG score recompute
- 2026-10-21 05:45 UTCVendor advisory
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-20 06:47 UTCEG score recompute
- 2026-10-20 06:47 UTCVendor advisory
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-19 07:50 UTCEG score recompute
- 2026-10-19 07:50 UTCVendor advisory
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-18 08:51 UTCVendor advisory
- 2026-10-18 03:23 UTCEG score recompute
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-17 06:16 UTCEG score recompute
- 2026-10-17 06:16 UTCVendor advisory
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-16 07:17 UTCEG score recompute
- 2026-10-16 07:17 UTCVendor advisory
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-15 06:13 UTCEG score recompute
- 2026-10-15 06:13 UTCVendor advisory
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-14 01:49 UTCEG score recompute
- 2026-10-14 01:49 UTCVendor advisory
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-12 22:02 UTCEG score recompute
- 2026-10-12 22:02 UTCVendor advisory
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-12 15:49 UTCEG score recompute
- 2026-10-12 06:14 UTCVendor advisory
- 2026-10-11 19:33 UTCEG score recompute
- 2026-10-11 16:48 UTCEG score recompute
- 2026-10-11 14:10 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-09 08:32 UTCEG score recompute
- 2026-10-09 08:32 UTCVendor advisory
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-08 09:17 UTCVendor advisory
- 2026-10-08 05:22 UTCEG score recompute
- 2026-10-08 05:22 UTCVendor advisory
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-07 10:06 UTCVendor advisory
- 2026-10-07 05:16 UTCVendor advisory
- 2026-10-07 01:16 UTCVendor advisory
- 2026-10-06 21:19 UTCVendor advisory
- 2026-10-06 16:53 UTCEG score recompute
- 2026-10-06 16:53 UTCVendor advisory
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-06 12:20 UTCVendor advisory
- 2026-10-06 07:52 UTCVendor advisory
- 2026-10-06 03:25 UTCVendor advisory
- 2026-10-06 03:24 UTCVendor advisory
- 2026-10-06 03:24 UTCVendor advisory
- 2026-10-05 17:44 UTCEG score recompute
- 2026-10-05 17:44 UTCVendor advisory
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 54th percentile
- 2026-10-05 13:52 UTCVendor advisory
- 2026-10-05 09:29 UTCVendor advisory
- 2026-10-05 05:28 UTCVendor advisory
- 2026-10-05 01:35 UTCVendor advisory
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:12:libevent
Same vendor
10 shownredhat:RHSA-2026:63388 · redhat:RHSA-2026:67908 · redhat:RHSA-2026:67909
Frequently asked(5)
What is CVE-2026-63382?
When was the CVE record for CVE-2026-63382 published?
Is CVE-2026-63382 actively exploited?
What is the CVSS score of CVE-2026-63382?
How do I remediate CVE-2026-63382?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-63382
Is Your Infrastructure Affected by CVE-2026-63382?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.