libexpat before 2.4.9 has a use-after-free in the doContent function in xmlparse.c.
CVE-2022-40674
“▲” beside the score: it is higher than NVD's CVSS score.
Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-09-15. NVD baseline CVSS 8.1; sources differ by 1.7.
Also known asEUVD-2022-43945 (ENISA EUVD) · GHSA-2vq2-xc55-3j5m (GitHub Security Advisories)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 8.1
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 45EG Risk 45/100
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)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation2.2% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable no (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. - EPSS PROB
- 2.2%
- EPSS %ILE
- 82nd
- 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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 2.2% 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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
September 14, 2022
Last Modified
October 14, 2026
Advisory Details (10)
Auto-updated Sep 18, 2026Mozilla Firefox: Multiple Vulnerabilities (GLSA 202211-06) — Gentoo security
https://security.gentoo.org/glsa/202211-06Expat: Multiple Vulnerabilities (GLSA 202209-24) — Gentoo security
https://security.gentoo.org/glsa/202209-24[SECURITY] Fedora 35 Update: mingw-expat-2.4.9-1.fc35 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XCGBVQQ47URGJAZWHCISHDWF6QBTV2LE/[SECURITY] Fedora 36 Update: expat-2.4.9-1.fc36 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WE2ZKEPGFCZ7R6DRVH3K6RBJPT42ZBEG/[SECURITY] Fedora 37 Update: mingw-expat-2.4.9-1.fc37 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LQB6FJAM5YQ35SF5B2MN25Y2FX56EOEZ/[SECURITY] Fedora 35 Update: expat-2.4.9-1.fc35 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J2IGJNHFV53PYST7VQV3T4NHVYAMXA36/[SECURITY] Fedora 36 Update: mingw-expat-2.4.9-1.fc36 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSVZN3IJ6OCPSJL7AEX3ZHSHAHFOGESK/[SECURITY] [DLA 3119-1] expat security update
https://lists.debian.org/debian-lts-announce/2022/09/msg00029.html[CVE-2022-40674] tests: Cover heap use-after-free issue in doContent (follow-up to #629)
Fix merged in libexpat/libexpat PR #640 on 2022-09-14 — awaiting tagged release
https://github.com/libexpat/libexpat/pull/640[CVE-2022-40674] Ensure raw tagnames are safe exiting internalEntityParser
Fix merged in libexpat/libexpat PR #629 on 2022-09-11 — awaiting tagged release
https://github.com/libexpat/libexpat/pull/629Vendor Advisories for CVE-2022-40674(20)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2023:3068Red Hat Product SecurityHigh
Red Hat Security Advisory: mingw-expat security update
- RHSA-2022:8841Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.51 SP1 security update
- RHSA-2022:8598Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Virtualization Host security update [ovirt-4.5.3-1]
- RHSA-2022:7025Red Hat Product SecurityHigh
Red Hat Security Advisory: firefox security update
- RHSA-2022:7024Red Hat Product SecurityHigh
Red Hat Security Advisory: firefox security update
- RHSA-2022:7023Red Hat Product SecurityHigh
Red Hat Security Advisory: thunderbird security update
- RHSA-2022:7020Red Hat Product SecurityHigh
Red Hat Security Advisory: firefox security update
- RHSA-2022:7026Red Hat Product SecurityHigh
Red Hat Security Advisory: thunderbird security update
- +12 more
Patch Availability(27)
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
(19 across 17 ecosystems)
Debian:11(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | 2.2.10-2, 2.2.10-2+deb11u1, 2.2.10-2+deb11u2, 2.2.10-2+deb11u3 |
| — |
| libxmltok | 1.2-4, 1.2-4.1, 1.2-4.1~exp1, 1.2-4.2 |
| — |
Debian:12(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
| libxmltok | 1.2-4, 1.2-4.1, 1.2-4.1~exp1, 1.2-4.2 |
| — |
Alpine:v3.13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.15(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.16(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.17(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.18(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.19(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.20(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Debian:10(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | 2.2.6-2, 2.2.6-2+deb10u1, 2.2.6-2+deb10u2, 2.2.6-2+deb10u3, 2.2.6-2+deb10u4 |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(5)
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.
- Microsoft MSRCCVE-2022-406742022-09-16
libexpat before 2.4.9 has a use-after-free in the doContent function in xmlparse.c.
- Red HatRHSA-2022:6831IMPORTANT2022-09-14
RHSA-2022:6831 — Important
- Red HatRHSA-2022:6832IMPORTANT2022-09-14
RHSA-2022:6832 — Important
- Red HatRHSA-2022:6833IMPORTANT2022-09-14
RHSA-2022:6833 — Important
- UbuntuUSN-5638-1MEDIUM
Expat vulnerability
Data Freshness Timeline
(refreshed 26× in last 7d / 93× 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 100 of 262 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. None are among the latest 100 rows. The 162 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 16:17 UTCVendor advisory
- 2026-11-01 16:17 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-31 16:58 UTCEG score recompute
- 2026-10-31 16:58 UTCVendor advisory
- 2026-10-31 16:58 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-31 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-30 17:35 UTCEG score recompute
- 2026-10-30 17:35 UTCVendor advisory
- 2026-10-30 17:35 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-30 16:30 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-29 18:21 UTCEG score recompute
- 2026-10-29 18:21 UTCVendor advisory
- 2026-10-29 18:21 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-29 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-28 19:08 UTCEG score recompute
- 2026-10-28 19:08 UTCVendor advisory
- 2026-10-28 19:08 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-28 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-27 19:32 UTCEG score recompute
- 2026-10-27 19:32 UTCVendor advisory
- 2026-10-27 19:32 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-27 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-26 20:19 UTCEG score recompute
- 2026-10-26 20:19 UTCVendor advisory
- 2026-10-26 20:18 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 moreShow fewer
- 2026-10-26 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-25 19:15 UTCVendor advisory
- 2026-10-25 19:15 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-25 18:00 UTCEG score recompute
- 2026-10-25 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-24 19:53 UTCEG score recompute
- 2026-10-24 19:53 UTCVendor advisory
- 2026-10-24 19:53 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-24 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-23 20:39 UTCEG score recompute
- 2026-10-23 20:39 UTCVendor advisory
- 2026-10-23 20:39 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-22 21:24 UTCEG score recompute
- 2026-10-22 21:24 UTCVendor advisory
- 2026-10-22 21:24 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-22 16:30 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-21 22:10 UTCEG score recompute
- 2026-10-21 22:10 UTCVendor advisory
- 2026-10-21 22:10 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-21 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-20 22:55 UTCEG score recompute
- 2026-10-20 22:55 UTCVendor advisory
- 2026-10-20 22:55 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-20 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-19 23:42 UTCEG score recompute
- 2026-10-19 23:42 UTCVendor advisory
- 2026-10-19 23:41 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-18 23:05 UTCEG score recompute
- 2026-10-18 23:05 UTCVendor advisory
- 2026-10-18 23:05 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-18 08:27 UTCEG score recompute
- 2026-10-17 23:49 UTCEG score recompute
- 2026-10-17 23:49 UTCVendor advisory
- 2026-10-17 23:49 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-17 00:34 UTCEG score recompute
- 2026-10-17 00:34 UTCVendor advisory
- 2026-10-17 00:34 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-16 16:35 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-16 00:19 UTCEG score recompute
- 2026-10-16 00:19 UTCVendor advisory
- 2026-10-16 00:18 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-15 16:28 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-14 18:17 UTCEG score recompute
- 2026-10-14 18:17 UTCVendor advisory
- 2026-10-14 18:17 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-14 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-13 17:25 UTCEG score recompute
- 2026-10-13 17:25 UTCVendor advisory
- 2026-10-13 17:24 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-13 16:29 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-12 18:08 UTCEG score recompute
- 2026-10-12 18:08 UTCVendor advisory
- 2026-10-12 18:08 UTCGHSA enrichmentGHSA-2vq2-xc55-3j5m · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-12 16:30 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-11 23:11 UTCEG score recompute
- 2026-10-11 13:44 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-10 19:57 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-08 17:05 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-07 23:45 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-05 17:40 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-04 23:19 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-03 14:23 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-02 16:23 UTCEPSS rescoreEPSS 2.2% · 82nd percentile
- 2026-10-01 19:47 UTCEPSS rescoreEPSS 2.2% · 81st percentile
- 2026-09-30 16:04 UTCEG score recompute
- 2026-09-30 15:01 UTCEPSS rescoreEPSS 2.2% · 81st percentile
- 2026-09-29 15:16 UTCEPSS rescoreEPSS 2.2% · 81st percentile
- 2026-09-28 13:48 UTCEPSS rescoreEPSS 2.2% · 81st percentile
- 2026-09-27 13:42 UTCEPSS rescoreEPSS 2.2% · 81st percentile
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Frequently asked(5)
What is CVE-2022-40674?
When was the CVE record for CVE-2022-40674 published?
Is CVE-2022-40674 actively exploited?
What is the CVSS score of CVE-2022-40674?
How do I remediate CVE-2022-40674?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2022-40674
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