SB2026081992 - Multiple vulnerabilities in libexpat
Published: August 19, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 13 vulnerabilities.
1) Integer overflow (CVE-ID: CVE-2026-56408)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in copyString when copying string data. A remote attacker can supply crafted XML input to cause memory corruption.
2) 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.
3) Out-of-bounds write (CVE-ID: CVE-2026-56132)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause memory corruption.
The vulnerability exists due to an out-of-bounds write in doProlog when processing scaffolding index data. A remote attacker can supply crafted XML input to cause memory corruption.
4) Integer overflow (CVE-ID: CVE-2026-56403)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in storeAtts when parsing XML attributes. A remote attacker can supply crafted XML input to cause memory corruption.
5) Integer overflow (CVE-ID: CVE-2026-56404)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in addBinding when processing XML data. A remote attacker can supply crafted XML input to cause memory corruption.
6) Integer overflow (CVE-ID: CVE-2026-56405)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in getAttributeId when parsing XML attributes. A remote attacker can supply crafted XML input to cause memory corruption.
7) Integer overflow (CVE-ID: CVE-2026-56406)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in XML_ParseBuffer when parsing buffered XML input. A remote attacker can supply crafted XML input to cause memory corruption.
8) Integer overflow (CVE-ID: CVE-2026-56407)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in textLen handling when parsing XML data. A remote attacker can supply crafted XML input to cause memory corruption.
9) 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.
10) Integer overflow (CVE-ID: CVE-2026-56409)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in the xmlwf output path join logic when joining output paths. A remote attacker can supply crafted input to cause memory corruption.
This issue affects the xmlwf tool.
11) Integer overflow (CVE-ID: CVE-2026-56410)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in xmlwf resolveSystemId when resolving system identifiers. A remote attacker can supply crafted input to cause memory corruption.
This issue affects the xmlwf tool.
12) Integer overflow (CVE-ID: CVE-2026-56411)
CWE-ID: CWE-190 - Integer overflow
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 an integer overflow in xmlwf notation list allocation when allocating notation list memory. A remote attacker can supply crafted input to cause memory corruption.
This issue affects the xmlwf tool.
13) 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.