CVE-2026-76956 Denial of service in libexpat

What is CVE-2026-76956?

CVE-2026-76956 is a medium-severity denial of service vulnerability in Libexpat Project Libexpat, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.

Weakness: CWE-394

Which versions are affected by CVE-2026-76956?

It affects 1 product.

Products include Libexpat Project Libexpat.

How do I fix CVE-2026-76956?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-76956 being exploited?

There is no known exploitation of CVE-2026-76956 in the wild and no public exploit code.

Other vulnerabilities in Libexpat Project Libexpat

• CVE-2024-45490 Integer overflow in n/a Critical 9.8
• CVE-2026-66046 Expat Denial of Service via storeAtts() Quadratic Complexity High 8.7
• CVE-2021-46143 Integer overflow in n/a High 8.1
• CVE-2017-11742 Privilege escalation in n/a High 7.8
• CVE-2025-59375 Denial of service in libexpat High 7.5

All Libexpat Project Libexpat vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2026-76956, AZL-96848, BELL-CVE-2026-76956, DEBIAN-CVE-2026-76956, ECHO-8a36-8d53-bf0c, GHSA-x282-q22w-c9hm and 1 more.