Xmlsoft libxml2 up to 2.15.3 Xmlcatalog Utility usershell stack-based overflow ⚔ [Disputed]

CVSS Meta Temp Score
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CTI Interest Score
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6.9$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Xmlsoft libxml2 up to 2.15.3. The impacted element is the function usershell of the component Xmlcatalog Utility. This manipulation causes stack-based overflow. This vulnerability appears as CVE-2026-11979. The attack may be initiated remotely. There is no available exploit. There are still doubts about whether this vulnerability truly exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Xmlsoft libxml2 up to 2.15.3. It has been declared as critical. Affected by this vulnerability is the function usershell of the component Xmlcatalog Utility. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. By supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame. Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process. This issue has been fixed in the commit c2e233fc. NOTE: The maintainers of this project did not agree that this issue is a vulnerability and considered it a bug.

It is possible to read the advisory at cert.pl. This vulnerability is known as CVE-2026-11979 since 06/11/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

The real existence of this vulnerability is still doubted at the moment. The vulnerability scanner Nessus provides a plugin with the ID 327570 (SUSE SLES16: libxml2-2 / libxml2-devel / libxml2-doc / libxml2-tools / etc (SUSE-SU-2026:22636-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability. Applying the patch c2e233fc1b341685fc99621b2768b503f777a72e is able to eliminate this problem. The bugfix is ready for download at gitlab.gnome.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (327570). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 6.9

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 327570
Nessus Name: SUSE SLES16: libxml2-2 / libxml2-devel / libxml2-doc / libxml2-tools / etc (SUSE-SU-2026:22636-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Patch: c2e233fc1b341685fc99621b2768b503f777a72e

Timelineinfo

06/11/2026 CVE reserved
06/29/2026 +18 days Advisory disclosed
06/29/2026 +0 days VulDB entry created
07/17/2026 +18 days VulDB entry last update

Sourcesinfo

Advisory: cert.pl
Status: Confirmed
Disputed: 🔍

CVE: CVE-2026-11979 (🔒)
GCVE (CVE): GCVE-0-2026-11979
GCVE (VulDB): GCVE-100-374623

Entryinfo

Created: 06/29/2026 16:37
Updated: 07/17/2026 19:21
Changes: 06/29/2026 16:37 (71), 07/04/2026 04:03 (11), 07/17/2026 19:21 (2)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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