xmlsoft libxml2 up to 2.15.3 URI Escape uri.c xmlURIEscapeStr integer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k1.21+

Summaryinfo

A vulnerability, which was classified as critical, was found in xmlsoft libxml2 up to 2.15.3. Affected by this vulnerability is the function xmlURIEscapeStr of the file uri.c of the component URI Escape. Such manipulation leads to integer overflow. This vulnerability is uniquely identified as CVE-2026-86139. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in xmlsoft libxml2 up to 2.15.3. It has been rated as critical. Affected by this issue is the function xmlURIEscapeStr of the file uri.c of the component URI Escape. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-86139 since 09/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 2.15.4 eliminates this vulnerability.

Once again VulDB remains the best source 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: 7.1
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

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

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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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: Yes

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-2026-86139 (🔒)
GCVE (CVE): GCVE-0-2026-86139
GCVE (VulDB): GCVE-100-399212

Entryinfo

Created: 09/05/2026 06:51
Changes: 09/05/2026 06:51 (67)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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