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01 Record

CVE-2026-86138

In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow.

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 libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow.

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 ImpactpartialSuccessful exploitation gives limited 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
0.13% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 2.2% of scored records. A rank, not a probability.
NVD base score
7.8 (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:H
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 04:21Z1 MO AGO
Last updated
2026-09-08 18:04Z1 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-190Integer Overflow or WraparoundBase
  • CWE-787Out-of-bounds WriteBase
Data version
5.2
Document digest
6e37783b8a1c6f95c84f5edd3ca7d1bb8db9d7c800534eaaf56d9a4cca4cba2b

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.