In doProlog in xmlparse.c in Expat (aka libexpat) before 2.4.3, an integer overflow exists for m_groupSize.
CVE-2021-46143
“—” beside the score: it is equal to NVD's CVSS score.
Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2022-02-10. NVD baseline CVSS 7.8; sources differ by 0.0.
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 7.8
- EG Score
- 7.8HIGHmedium confidence
- EG Risk
- 51EG Risk 51/100
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)Severity78% × 45%Impact severity (EG Severity): CVSS 7.8 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.Automatability0% × 15%CISA's SSVC Automatable value: no (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 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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 4.2%
- EPSS %ILE
- 90th
- 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 its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 4.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-21). 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: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: 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 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.
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
January 6, 2022
Last Modified
October 14, 2026
Advisory Details (8)
Auto-updated Sep 11, 2026oss-security - Expat 2.4.3 released, includes 8 security fixes
http://www.openwall.com/lists/oss-security/2022/01/17/3[R1] Nessus Versions 8.15.3 and 10.1.1 Fix Multiple Third-Party Vulnerabilities - Security Advisory | Tenable®
https://www.tenable.com/security/tns-2022-05Expat: Multiple Vulnerabilities (GLSA 202209-24) — Gentoo security
https://security.gentoo.org/glsa/202209-24[CVE-2021-46143] lib: Prevent integer overflow on m_groupSize in function doProlog (fixes #532)
Fix merged in libexpat/libexpat PR #538 on 2022-01-10 — awaiting tagged release
https://github.com/libexpat/libexpat/pull/538[CVE-2021-46143] Crafted XML file can cause integer overflow on m_groupSize in function doProlog · Issue #532 · libexpat/libexpat · GitHub
https://github.com/libexpat/libexpat/issues/532Vendor Advisories for CVE-2021-46143(9)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2025:22871Red Hat Product SecurityHigh
Red Hat Security Advisory: expat security update
- RHSA-2025:22785Red Hat Product SecurityHigh
Red Hat Security Advisory: expat security update
- RHSA-2022:7692Red Hat Product SecurityMedium
Red Hat Security Advisory: xmlrpc-c security update
- RHSA-2022:7144Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.51 security update
- RHBA-2022:4046Red Hat Product SecurityHigh
Red Hat Bug Fix Advisory: new packages: expat
- RHSA-2022:1069Red Hat Product SecurityHigh
Red Hat Security Advisory: expat security update
- RHSA-2022:0951Red Hat Product SecurityHigh
Red Hat Security Advisory: expat security update
- GHSA-j6g2-cvhq-p8xrGitHub Security AdvisoriesHigh
In doProlog in xmlparse.c in Expat (aka libexpat) before 2.4.3, an integer overflow exists for...
- +1 more
Patch Availability(11)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libxmltok1-dev (1.2-4ubuntu0.22.04.1~esm4) @ jammy | 2026-10-21 | ubuntu |
| ubuntu | lib64expat1 (2.1.0-7ubuntu0.16.04.5+esm2) @ xenial | 2026-10-21 | ubuntu |
| ubuntu | mame-tools (0.264+dfsg.1-1ubuntu0.1~esm1) @ noble | 2026-10-21 | ubuntu |
| ubuntu | libxmltok1-dev (1.2-4ubuntu0.20.04.1~esm1) @ focal | 2026-10-21 | ubuntu |
| redhat | expat-0:2.2.10-1.el8_2 | 2025-12-09 | redhat |
| redhat | expat-0:2.2.10-1.el8_4 | 2025-12-04 | redhat |
| redhat | xmlrpc-c-0:1.51.0-8.el8 | 2022-11-08 | redhat |
| redhat | expat | 2022-10-26 | redhat |
| redhat | expat-0:2.2.10-12.el9_0 | 2022-05-17 | redhat |
| redhat | expat-0:2.1.0-14.el7_9 | 2022-03-28 | redhat |
| redhat | expat-0:2.2.5-4.el8_5.3 | 2022-03-16 | 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
(21 across 19 ecosystems)
Debian:11(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | 2.2.10-2 |
| — |
| 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:v3.12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
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 |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | — |
| — |
Debian:9(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| expat | 2.2.0-2, 2.2.0-2+deb9u1, 2.2.0-2+deb9u2, 2.2.0-2+deb9u3 |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(4)
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 11× in last 7d / 43× 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 97 of 200 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 103 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-21 22:11 UTCEG score recompute
- 2026-10-21 22:11 UTCVendor advisory
- 2026-10-21 22:11 UTCGHSA enrichmentGHSA-j6g2-cvhq-p8xr · GitHub severity HIGH · GitHub CVSS 7.8
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-18 08:50 UTCEG score recompute
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-16 16:34 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-15 16:28 UTCEPSS rescoreEPSS 4.2% · 90th percentile
- 2026-10-14 16:29 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-14 13:35 UTCEG score recompute▼ 0.30
- 2026-10-14 13:35 UTCVendor advisory
- 2026-10-14 13:35 UTCGHSA enrichmentGHSA-j6g2-cvhq-p8xr · GitHub severity HIGH · GitHub CVSS 7.8
- 2026-10-14 13:25 UTCNVD updateCVSS v3 → 7.8
- 2026-10-14 12:33 UTCEG score recompute
- 2026-10-14 12:33 UTCVendor advisory
- 2026-10-14 12:32 UTCGHSA enrichmentGHSA-j6g2-cvhq-p8xr · GitHub severity HIGH · GitHub CVSS 7.8
- 2026-10-13 16:28 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-12 19:06 UTCEG score recompute
- 2026-10-12 16:30 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-11 23:32 UTCEG score recompute
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- 2026-10-11 13:44 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-08 16:40 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-07 23:45 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-06 15:14 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-05 17:40 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-04 23:19 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-03 14:22 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-10-02 16:23 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-30 15:44 UTCEG score recompute
- 2026-09-30 15:00 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-29 15:15 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-28 13:47 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-26 15:54 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-26 00:21 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-25 08:36 UTCOSV refresh
- 2026-09-24 14:00 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-23 13:45 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-22 14:44 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-21 20:28 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-20 20:13 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-19 15:38 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-18 19:24 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-17 19:23 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-16 14:05 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-15 03:06 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-12 14:57 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-11 14:49 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-11 09:33 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-08 21:57 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-07 15:58 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-06 13:45 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-05 23:55 UTCOSV refresh
- 2026-09-05 15:25 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-04 13:57 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-04 05:03 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-02 14:09 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-09-01 13:51 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-30 19:14 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-30 01:19 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-28 21:38 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-27 14:22 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-26 14:43 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-25 13:46 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-24 14:13 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-21 23:46 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-20 22:52 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-19 17:01 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-19 11:02 UTCOSV refresh
- 2026-08-18 13:45 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-17 13:44 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-16 14:53 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-16 02:11 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-15 01:27 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-13 21:57 UTCEPSS rescoreEPSS 3.8% · 89th percentile
- 2026-08-12 13:48 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-11 13:38 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-09 13:44 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-08 16:34 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-07 16:24 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-06 13:44 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-05 19:15 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-04 15:06 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-04 10:34 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-04 06:57 UTCOSV refresh
- 2026-08-03 10:33 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-02 02:24 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-08-01 04:13 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-07-30 16:25 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-07-30 01:28 UTCEPSS rescoreEPSS 3.8% · 88th percentile
- 2026-07-28 15:33 UTCEPSS rescoreEPSS 3.8% · 88th percentile
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:9:expat
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Same vendor
10 shownredhat:RHBA-2022:4046 · redhat:RHSA-2022:0951
- CVE-2022-22824EG 9.8CRITICAL
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- CVE-2022-22822EG 9.8EPSS p92CRITICAL
- CVE-2022-22827EG 8.8HIGH
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- CVE-2022-25235EG 9.8EPSS p92CRITICAL
- CVE-2021-45960EG 8.8EPSS p91HIGH
- CVE-2022-25236EG 9.8EPSS p98CRITICAL
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Same CWE
10 shownCWE-190
Frequently asked(5)
What is CVE-2021-46143?
When was the CVE record for CVE-2021-46143 published?
Is CVE-2021-46143 actively exploited?
What is the CVSS score of CVE-2021-46143?
How do I remediate CVE-2021-46143?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-46143
Is Your Infrastructure Affected by CVE-2021-46143?
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