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CVE-2026-115506 Details

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:7.5 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/hannob/lololol	[email protected]	Patch
https://github.com/libexpat/libexpat	[email protected]	Product
https://github.com/libexpat/libexpat/issues/1160	[email protected]	Issue TrackingVendor Advisory
https://github.com/libexpat/libexpat/pull/1433	[email protected]	Patch
https://www.vulncheck.com/advisories/libexpat-through-2.9.0-denial-of-service-via-billion-laughs-detection-delay	[email protected]	PatchThird Party Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-776	Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')	[email protected]

Affected Products

Product	Versions
libexpat project libexpat	<= 2.9.0
CPE cpe:2.3:a:libexpat_project:libexpat:::::::: Remediation No remediation found in references.

Change History

3 change records found show changes

Date	Action	Recorded By
Nov 2, 2026	Initial Analysis	[email protected]
Oct 23, 2026	CVE Modified	CISA-ADP
Oct 22, 2026	New CVE Received	[email protected]