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Fencer Vulns
medium 6.9

CVE-2026-86139 json

In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.

published 2026-09-05 2 mo ago modified 2026-09-15 54 d ago also EUVD-2026-71832

cvss
6.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.

Patch / fix

  • xmlsoft libxml2 2.15.4
  • libxml2 Debian 14 2.15.4+dfsg-1

debian advisories DEBIAN-CVE-2026-86139

  • libxml2 Ubuntu 26.04 LTS 2.15.2+dfsg-0.1ubuntu0.3

ubuntu advisories UBUNTU-CVE-2026-86139

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libxml2 hummingbird 1 2.15.4-0.1.hum1
  • libxml2-16 hummingbird 1 2.15.4-0.1.hum1
  • python3-libxml2 hummingbird 1 2.15.4-0.1.hum1

red hat advisories RHSA-2026:64463

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-86139 updated cvss 6.9

libxml2: libxml2: Integer overflow in xmlURIEscapeStr may lead to arbitrary code execution

  • Red Hat Hardened Images libxml2 2.15.4-0.1.hum1, libxml2-16 2.15.4-0.1.hum1, python3-libxml2 2.15.4-0.1.hum1
    fixed: vendor fix RHSA-2026:64463
  • Red Hat Enterprise Linux 6 libxml2, libxml2-python Red Hat Enterprise Linux 7 libxml2, libxml2-python Red Hat Enterprise Linux 8 podman, libxml2, podman-tests, podman-docker, podman-remote, podman-gvproxy, +4 more Red Hat Enterprise Linux 9 podman, libxml2, podman-tests, podman-docker, podman-remote, podman-gvproxy, +3 more Red Hat Enterprise Linux 10 podman, libxml2 Red Hat Hardened Images swift-lang
    +2 more products
    Red Hat OpenShift Container Platform 4 podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, podman-plugins, +4 more Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.9 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • xmlsoft libxml2

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.