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🛡️ CVE-2026-45186 — libexpat

🟢 CVSS 2.9 — Low ⚠️ Exploit Public CWE-407 NVD
2.9
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

CVE-2026-45186 is classified as CWE-407: Inefficient Algorithmic Complexity. Crafted input drives an algorithm into its worst case, so a small request costs disproportionate work.

Affected software

CVE-2026-45186 is recorded against 1 package.

  • libexpat (fixed in 2.8.1)

Timeline and source

Published on 10 May 2026 and last revised on 24 July 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
www.openwall.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
bugzilla.redhat.com
cert-portal.siemens.com
security.access.redhat.com

Other advisories for this package

libexpat has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-407: Inefficient Algorithmic Complexity) in other software:

Details

Severity LOW
CVSS Score 2.9
CVSS Vector CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE CWE-407
Public Exploit ⚠️ Yes
Source NVD
Published 2026-05-10
Updated 2026-08-20
Modified 2026-07-24

Affected Packages

Software From version Fixed in
libexpat 2.8.1

Similar Threats

Exploit Protection

Are you running libexpat?

CVE-2026-45186 carries CVSS 2.9 Low rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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