SB2026091553 - openEuler 24.03 LTS SP1 update for expat

Description

This security bulletin contains information about 6 vulnerabilities.

1) Inefficient Algorithmic Complexity (CVE-ID: CVE-2026-66046)

CWE-ID: CWE-407 - Inefficient Algorithmic Complexity

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to algorithmic complexity in attribute declaration handling when parsing XML documents with numerous attributes. A remote attacker can submit a crafted XML document to cause a denial of service.

2) Inefficient Algorithmic Complexity (CVE-ID: CVE-2026-76641)

CWE-ID: CWE-407 - Inefficient Algorithmic Complexity

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an inefficient algorithm in attribute isCdata lookups when parsing crafted XML input. A remote attacker can submit moderately sized crafted XML input to cause a denial of service.

A compression layer around XML can significantly reduce the minimum attack payload size.

3) Use-after-free (CVE-ID: CVE-2026-76957)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a lack of handler call depth tracking with custom encoding callbacks. A remote attacker can pass specially crafted XML input to the application, trigger a use-after-free error and perform a denial of service attack.

4) Protection mechanism failure (CVE-ID: CVE-2026-50219)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory corruption.

The vulnerability exists due to missing control flow integrity checks in XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, and XML_ParserReset when these functions are called reentrantly from bindings or callbacks. A remote attacker can trigger unsafe parser API calls to cause memory corruption.

The issue is described as relevant to language bindings.

5) Protection mechanism failure (CVE-ID: CVE-2026-56131)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory corruption.

The vulnerability exists due to missing control flow integrity checks in XML_ResumeParser when it is called from a handler. A remote attacker can trigger a handler-driven call to XML_ResumeParser to cause memory corruption.

This issue is described as a hole in the fix for CVE-2026-50219.

6) Protection mechanism failure (CVE-ID: CVE-2026-56412)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory corruption.

The vulnerability exists due to missing control flow integrity checks in doCdataSection when handling XML_TOK_DATA_CHARS callbacks. A remote attacker can trigger unsafe handler calls to cause memory corruption.

This issue is described as a hole in the fix for CVE-2026-50219.

Remediation

Install update from vendor's website.

References

• https://www.openeuler.org/en/security/security-bulletins/detail/?id=openEuler-SA-2026-3671