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Public proof of conceptFix available

CVE-2021-45960

A public proof of concept exists; no exploitation attested.

  • Published2022-01-01
  • WeaknessCWE-682

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 Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory).

Timeline

dates in UTC
  1. 2022-01-0119:15CVE publishedNVD

Versions per branch

NVD
Netapp hci baseboard management controller
BranchAffectedFixed in
—= h610cno fix published
—= h610sno fix published
—= h615cno fix published
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
11.0= 11.0no fix published
Tenable nessus
BranchAffectedFixed in
10.x≥ 10.0.0, < 10.1.110.1.1
8.15< 8.15.38.15.3

5 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
  • expatUbuntu:Pro:16.04:LTSall versions · fixed in 2.1.0-7ubuntu0.16.04.5+esm2
  • expatUbuntu:Pro:14.04:LTSall versions · fixed in 2.1.0-4ubuntu1.4+esm4
  • expatUbuntu:22.04:LTSall versions · fixed in 2.4.3-1
  • expatUbuntu:20.04:LTSall versions · fixed in 2.2.9-1ubuntu0.2
  • expatUbuntu:18.04:LTSall versions · fixed in 2.2.5-3ubuntu0.4
  • expatTuxCare:OracleLinux:6all versions · fixed in 2.0.1-13.el6_8.tuxcare.els1and 1 other package
  • expatTuxCare:CentOS:8.5all versions · fixed in 2.2.5-4.el8.tuxcare.els1and 2 other packages

99 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-45960 Red Hat Product Security92 products fixed · 33 known affected

    expat: Large number of prefixed XML attributes on a single tag can crash libexpat

    expat as a component of Red Hat Enterprise Linux 6 · expat-devel as a component of Red Hat Enterprise Linux 6 · expat.src as a component of Red Hat Enterprise Linux 6 · +30 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

  • 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

  • ICSA-23-278-01 CISA8 known affected

    Hitachi Energy AFS65x,AFF66x, AFS67x, and AFR67x Series Products

    AFF66X FW: <= 03.0.02 · AFS66X-S: vers:all/* · AFS660-C: vers:all/* · +5 more

5 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 CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  3. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  4. Vendor fix CISA ICSA-23-278-01 · 1 productAFF66X FW 03.0.02 and earlier: For all vulnerabilities, apply mitigation strategy as described in Hitachi Energy's general mitigation factors below or update to upcoming AFF66X 04.x.xx FW when released.
  5. Vendor fix CISA ICSA-23-278-01 · 4 productsAFS66X-S, AFS660-C, AFS66X-B, AFS670-V20 devices: For all vulnerabilities, apply mitigation strategy as described in Hitachi Energy's general mitigation factors below or update to upcoming AFS66X, AFS670-V20 7.1.08 FW when released. Disable HTTP/HTTPS server or restrict access to HTTP/HTTPS to trus…
  6. Vendor fix CISA ICSA-23-278-01 · 3 productsAFS65X, AFS67X, AFR677 devices: For all vulnerabilities, apply mitigation strategy as described in Hitachi Energy's general mitigation factors below or update to AFS65X, AFS67X, AFR677 09.1.08 FW. Disable HTTP/HTTPS server or restrict access to HTTP/HTTPS to trusted IP addresses. Disable IEC61850-M…

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:L/UI:N/S:U/C:H/I:H/A:H
Published
2022-01-01
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-pfmv-2r4f-j9mj

Frequently asked questions

What is CVE-2021-45960?

In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory).

Is CVE-2021-45960 actively exploited?

A proof-of-concept exploit exists for CVE-2021-45960, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-45960?

CVE-2021-45960 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record