---
id: CVE-2026-86139
title: 'In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.'
summary: 'In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.'
severity: medium
cvss: 6.9
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L'
cwe:
  - CWE-190
vendor: xmlsoft
product: libxml2
affected:
  - libxml2 < 2.15.4
patched:
  - libxml2 2.15.4
published: '2026-09-05'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T19:39:45.267'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86139'
references:
  - url: >-
      https://github.com/GNOME/libxml2/commit/8edbbdb09f24d26a2f900141fddc2b9d014f53b0
    label: cve@mitre.org
  - url: 'https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4'
    label: cve@mitre.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86139.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-86139'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2528991'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-86139'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86139'
  - url: 'https://access.redhat.com/errata/RHSA-2026:64463'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00113
epssPercentile: 0.01634
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-08T13:04:02.900168Z'
ingestedAt: '2026-09-06T02:48:38.625Z'
---

## Overview

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

## Affected

- `libxml2 < 2.15.4`

## Remediation

Upgrade past the affected range:

- `libxml2 2.15.4`

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Hardened Images · no fix planned: Red Hat Hardened Images · updated 2026-09-08 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86139.json)
- **RHSA-2026:64463** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:64463)