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HIGH

CVE-2021-46143

CVSS v3

7.8

HIGH

EPSS Score

4.2 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

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

  • expatAlmaLinux:8all versions · fixed in 2.2.5-8.el8_6.2and 1 other package
  • xmlrpc-cAlmaLinux:8all versions · fixed in 1.51.0-8.el8and 4 other packages

Vendor advisories

  • CVE-2021-46143 Red Hat Product Security209 products fixed · 27 known affected

    expat: Integer overflow in doProlog in xmlparse.c

    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

  • 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)

  • 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

  • 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/*

7 more advisories

Full record on NVD

Description

In doProlog in xmlparse.c in Expat (aka libexpat) before 2.4.3, an integer overflow exists for m_groupSize.

Technical details

Published
2022-01-06

Frequently asked questions

What is CVE-2021-46143?

In doProlog in xmlparse.c in Expat (aka libexpat) before 2.4.3, an integer overflow exists for m_groupSize.

Is CVE-2021-46143 actively exploited?

Active exploitation of CVE-2021-46143 has not been confirmed. Its EPSS score was 4.2% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-46143?

CVE-2021-46143 has a CVSS v3 base score of 7.8 (HIGH severity).

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