libexpat 2.7.2 through 2.9.0 contains a denial of service vulnerability because XML_ParserReset zeroes the direct byte count but never offsets tracked heap allocations. Attackers can submit a large XML document so later documents on the same reset parser fail with XML_ERROR_NO_MEMORY until it is recreated.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
libexpat libexpat unaffected
Version Status Constraints
2.7.2 affected ≤ 2.9.0

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Project Subscriptions

Vendors Products
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Libexpat Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/libexpat/libexpat cve-icon cve-icon
https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L1560 cve-icon cve-icon
https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L860-L884 cve-icon cve-icon
https://github.com/libexpat/libexpat/pull/1431 cve-icon cve-icon
https://www.vulncheck.com/advisories/libexpat-2.7.2-through-2.9.0-denial-of-service-via-xml-parserreset cve-icon cve-icon
History

Tue, 20 Oct 2026 12:45:00 +0000

Type Values Removed Values Added
Description libexpat 2.7.2 through 2.9.0 contains a denial of service vulnerability because XML_ParserReset zeroes the direct byte count but never offsets tracked heap allocations. Attackers can submit a large XML document so later documents on the same reset parser fail with XML_ERROR_NO_MEMORY until it is recreated.
Title libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset
First Time appeared Libexpat Project
Libexpat Project libexpat
Weaknesses CWE-909
CPEs cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
Vendors & Products Libexpat Project
Libexpat Project libexpat
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-20T16:06:48.218Z

Reserved: 2026-10-20T01:07:45.687Z

Link: CVE-2026-113351

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-20T11:17:19.363

Modified: 2026-10-20T11:17:19.363

Link: CVE-2026-113351

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-20T15:00:19Z

Weaknesses