synced 9 MIN AGO
01 Record

CVE-2026-86143

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling

MediumPUBLISHEDCNA: mitre
CNA base score6.9 CVSS v3.xCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
View raw JSON

02 Description

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.19% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 8.9% of scored records. A rank, not a probability.
NVD base score
7.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
NVD analysis status
Analyzed. NVD last modified this record on 2026-09-15.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-09-05 04:31Z1 MO AGO
Last updated
2026-09-08 18:06Z1 MO AGO
Reserved
2026-09-05
Assigning CNA
mitre
Record state
PUBLISHED
Severity
Medium (CVSS 6.9)
CNA CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
Weaknesses
  • CWE-192Integer Coercion ErrorVariant
  • CWE-190Integer Overflow or WraparoundBase
Data version
5.2
Document digest
ec386011f56f722662cfc9a2dd651c950d95b45fad782e338f53f7f3fe662d73

05 Affected products

VendorProductVersionsPlatforms
xmlsoftlibxml20 to < 2.15.4—

06 References

07 Fixed in

AlmaLinux 8

  • libxml2
    Fixed in 2.9.7-21.el8_10.9
  • libxml2-devel
    Fixed in 2.9.7-21.el8_10.9
  • python3-libxml2
    Fixed in 2.9.7-21.el8_10.9

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 9

  • libxml2
    Fixed in 2.9.13-14.el9_8.5
  • libxml2-devel
    Fixed in 2.9.13-14.el9_8.5
  • python3-libxml2
    Fixed in 2.9.13-14.el9_8.5

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 10

  • libxml2
    Fixed in 2.12.5-10.el10_2.4
  • libxml2-devel
    Fixed in 2.12.5-10.el10_2.4
  • libxml2-static
    Fixed in 2.12.5-10.el10_2.4
  • python3-libxml2
    Fixed in 2.12.5-10.el10_2.4

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 8

  • libxml2
    Fixed in 2.9.7-21.el8_10.9
  • libxml2-devel
    Fixed in 2.9.7-21.el8_10.9
  • python3-libxml2
    Fixed in 2.9.7-21.el8_10.9

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 9

  • libxml2
    Fixed in 2.9.13-14.el9_8.5
  • libxml2-devel
    Fixed in 2.9.13-14.el9_8.5
  • python3-libxml2
    Fixed in 2.9.13-14.el9_8.5

Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 10

  • libxml2
    Fixed in 2.12.5-10.el10_2.4
  • libxml2-devel
    Fixed in 2.12.5-10.el10_2.4
  • libxml2-static
    Fixed in 2.12.5-10.el10_2.4
  • python3-libxml2
    Fixed in 2.12.5-10.el10_2.4

Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • libxml2
    No fix yet

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • libxml2
    No fix yet

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • libxml2
    Fixed in 2.15.4+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • libxml2
    Fixed in 2.9.13+dfsg-1ubuntu0.14

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 24.04 LTS

  • libxml2
    Fixed in 2.9.14+dfsg-1.3ubuntu3.10

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 26.04 LTS

  • libxml2
    Fixed in 2.15.2+dfsg-0.1ubuntu0.3

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

  • libxml2
    Fixed in 2.9.1+dfsg1-3ubuntu4.13+esm13
    Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 16.04 LTS

  • libxml2
    Fixed in 2.9.3+dfsg1-1ubuntu0.7+esm14
    Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 18.04 LTS

  • libxml2
    Fixed in 2.9.4+dfsg1-6.1ubuntu1.9+esm9
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 20.04 LTS

  • libxml2
    Fixed in 2.9.10+dfsg-5ubuntu0.20.04.10+esm6
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.