libexpat up to 2.8.1 xmlparse.c doProlog incorrect synchronization

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k1.05

Summaryinfo

A vulnerability was found in libexpat up to 2.8.1 and classified as problematic. Affected by this vulnerability is the function doProlog of the file xmlparse.c. The manipulation results in incorrect synchronization. This vulnerability is identified as CVE-2026-56132. The attack is only possible with local access. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in libexpat up to 2.8.1. Affected is the function doProlog of the file xmlparse.c. The manipulation with an unknown input leads to a incorrect synchronization vulnerability. CWE is classifying the issue as CWE-821. The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In libexpat before 2.8.2, there is a heap-based buffer overflow in doProlog in xmlparse.c because scaffold backing array reallocation is mishandled when there is data-structure sharing across parsers.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-56132 since 06/19/2026. The exploitability is told to be difficult. Local access is required to approach this attack. Technical details are known, but there is no available exploit.

Upgrading to version 2.8.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-2008). If you want to get best quality of vulnerability data, you may have to visit VulDB.

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: Incorrect synchronization
CWE: CWE-821
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

06/19/2026 Advisory disclosed
06/19/2026 +0 days CVE reserved
06/19/2026 +0 days VulDB entry created
06/19/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-56132 (🔒)
GCVE (CVE): GCVE-0-2026-56132
GCVE (VulDB): GCVE-100-372306
CERT Bund: WID-SEC-2026-2008 - expat: Mehrere Schwachstellen

Entryinfo

Created: 06/19/2026 07:55
Updated: 06/19/2026 11:31
Changes: 06/19/2026 07:55 (63), 06/19/2026 11:31 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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