xmlsoft libxml2 up to 2.15.3 xmlIO xmlOutputWriteCallback integer overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k2.40

Summaryinfo

A vulnerability, which was classified as problematic, has been found in xmlsoft libxml2 up to 2.15.3. Affected is the function xmlOutputWriteCallback of the component xmlIO. This manipulation causes integer overflow. This vulnerability is handled as CVE-2026-86143. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability was found in xmlsoft libxml2 up to 2.15.3. It has been declared as problematic. Affected by this vulnerability is the function xmlOutputWriteCallback of the component xmlIO. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-86143 since 09/05/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.15.4 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.1
VulDB Meta Temp Score: 6.0

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
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: libxml2 2.15.4

Timelineinfo

09/05/2026 Advisory disclosed
09/05/2026 +0 days CVE reserved
09/05/2026 +0 days VulDB entry created
09/05/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-86143 (🔒)
GCVE (CVE): GCVE-0-2026-86143
GCVE (VulDB): GCVE-100-399211

Entryinfo

Created: 09/05/2026 06:51
Changes: 09/05/2026 06:51 (66)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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