libexpat up to 2.8.1 integer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.6$0-$5k5.81-

Summaryinfo

A vulnerability labeled as problematic has been found in libexpat up to 2.8.1. Affected by this issue is some unknown functionality. The manipulation results in integer overflow. This vulnerability was named CVE-2026-56411. The attack needs to be approached locally. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in libexpat up to 2.8.1. Affected is an unknown part. The manipulation with an unknown input leads to a integer overflow vulnerability. CWE is classifying the issue as CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-56411 since 06/21/2026. The exploitability is told to be difficult. The attack needs to be approached locally. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.8.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-38188) and CERT Bund (WID-SEC-2026-2025). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Open Source expat

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 4.5
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.9
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: libexpat 2.8.2

Timelineinfo

06/21/2026 Advisory disclosed
06/21/2026 +0 days CVE reserved
06/21/2026 +0 days VulDB entry created
06/22/2026 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-56411 (🔒)
GCVE (CVE): GCVE-0-2026-56411
GCVE (VulDB): GCVE-100-372648
EUVD: 🔒
CERT Bund: WID-SEC-2026-2025 - libexpat: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Entryinfo

Created: 06/21/2026 19:19
Updated: 06/22/2026 12:52
Changes: 06/21/2026 19:19 (61), 06/21/2026 20:25 (1), 06/22/2026 12:52 (7)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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