Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion') Affecting expat package, versions *


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.46% (40th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-EXPAT-21479163
  • published23 Oct 2026
  • disclosed22 Oct 2026

Introduced: 22 Oct 2026

NewCVE-2026-115506  (opens in a new tab)
CWE-776  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable expat.

NVD Description

Note: Versions mentioned in the description apply only to the upstream expat package and not the expat package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

libexpat through 2.9.0 contains a denial of service vulnerability because billion laughs protection in accountingDiffTolerated() in xmlparse.c detects entity amplification too late. Attackers can supply a moderately sized XML document with a large DTD and nested entity expansions to consume tens of seconds of CPU per parse.

CVSS Base Scores

version 3.1