---
id: CVE-2026-45186
title: >-
  In libexpat before 2.8.1, the computational complexity of attribute name
  collision checks allows a denial of service via moderately sized crafted XML
  input.
summary: >-
  In libexpat before 2.8.1, the computational complexity of attribute name
  collision checks allows a denial of service via moderately sized crafted XML
  input.
severity: low
cvss: 2.9
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-407
vendor: libexpat_project
product: libexpat
affected:
  - libexpat < 2.8.1
patched:
  - libexpat 2.8.1
published: '2026-05-10'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:17:58.967'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45186'
references:
  - url: 'https://github.com/libexpat/libexpat/pull/1216'
    label: cve@mitre.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/05/11/16'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2026:22715'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:22721'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:23230'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26319'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:27201'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:29197'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:58981'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-45186'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2468575'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45186.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-45186'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45186'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00563
epssPercentile: 0.44488
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-05-11T15:01:28.359121Z'
ingestedAt: '2026-09-16T12:55:21.869Z'
scores:
  nvd: 2.9
  vendor: 7.5
---

## Overview

In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.

## Affected

- `libexpat < 2.8.1`

## Remediation

Upgrade past the affected range:

- `libexpat 2.8.1`

## Vendor advisories

- **RHSA-2026:22715** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-06-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:22715)
- **RHSA-2026:23230** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-06-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:23230)
- **RHSA-2026:22721** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-06-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:22721)
- **RHSA-2026:29197** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-06-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:29197)
- **RHSA-2026:27201** · Red Hat · fixed in: Red Hat JBoss Core Services 2.4.62.SP4 · released 2026-06-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:27201)
- **RHSA-2026:58981** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:58981)
- **RHSA-2026:26319** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-06-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:26319)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45186.json)