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Public proof of conceptFix available

CVE-2022-43680

A public proof of concept exists; no exploitation attested.

  • Published2022-10-24
  • WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate in out-of-memory situations.

Timeline

dates in UTC
  1. 2022-10-2414:15CVE publishedNVD

Versions per branch

NVD
Fedoraproject fedora
BranchAffectedFixed in
35.x= 35no fix published
36.x= 36no fix published
37.x= 37no fix published
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
11.0= 11.0no fix published
Libexpat project libexpat
BranchAffectedFixed in
2.4≤ 2.4.9no fix published

9 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • coin3Ubuntu:Pro:18.04:LTSall versions · no fixed version listedand 2 other packages
  • expatWolfiall versions · fixed in 0
  • expatUbuntu:Pro:16.04:LTSall versions · fixed in 2.1.0-7ubuntu0.16.04.5+esm7
  • expatUbuntu:Pro:14.04:LTSall versions · fixed in 2.1.0-4ubuntu1.4+esm7
  • expatUbuntu:22.04:LTSall versions · fixed in 2.4.7-1ubuntu0.2
  • expatUbuntu:22.04:LTSall versions · fixed in 2.4.7-1ubuntu0.1
  • expatUbuntu:20.04:LTSall versions · fixed in 2.2.9-1ubuntu0.6
  • expatUbuntu:20.04:LTSall versions · fixed in 2.2.9-1ubuntu0.5

126 more package ranges on OSV.dev

Vendor advisories

  • CVE-2022-43680 Red Hat Product Security141 products fixed · 29 known affected

    expat: use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate

    compat-expat1 as a component of Red Hat Enterprise Linux 6 · compat-expat1.src as a component of Red Hat Enterprise Linux 6 · expat as a component of Red Hat Enterprise Linux 6 · +26 more

  • RHSA-2025:22871 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: expat security update

  • RHSA-2025:22785 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: expat security update

  • RHSA-2024:0421 Red Hat Product Security21 products fixed

    Red Hat Security Advisory: expat security update

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more

11 more advisories

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2025:22871 · 2 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Vendor fix Red Hat Product Security RHSA-2024:0421 · 21 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing the updated packages, applications using the Expat library must be restarted for the update to take effect.
  3. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  4. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  5. Vendor fix Red Hat Product Security RHSA-2023:3355 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  6. Vendor fix CISA ICSA-23-143-01 · 7 productsHitachi Energy has released the following mitigations/fixes:

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2022-10-24
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-4hjv-8mmr-jxwv

Frequently asked questions

What is CVE-2022-43680?

In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate in out-of-memory situations.

Is CVE-2022-43680 actively exploited?

Active exploitation of CVE-2022-43680 has not been confirmed. Its EPSS score was 3.2% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2022-43680?

CVE-2022-43680 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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