OESA-2026-4374 (CVE-2026-76781)

Vulnerability from osv_openeuler – Published: 2026-10-16 11:59 – Updated: 2026-10-16 11:59 – Source website
VLAI
Summary
libxml2 security update
Details

This library allows to manipulate XML files. It includes support to read, modify and write XML and HTML files. There is DTDs support this includes parsing and validation even with complex DtDs, either at parse time or later once the document has been modified. The output can be a simple SAX stream or and in-memory DOM like representations. In this case one can use the built-in XPath and XPointer implementation to select sub nodes or ranges. A flexible Input/Output mechanism is available, with existing HTTP and FTP modules and combined to an URI library.

Security Fix(es):

A flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a nextCatalog element lacks its mandatory catalog attribute, leading to the application crashing and causing a Denial of Service (DoS).(CVE-2026-76781)

In libxml2 before 2.15.4, there is a heap-based buffer overflow in xmlXPtrEvalXPtrPart because of xmlXPtrEval xpointer length saturation.(CVE-2026-86142)

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.(CVE-2026-86143)

In xinclude in libxml2 before 2.15.4, xmlXIncludeProcess and xmlXIncludeProcessTree do not propagate parseFlags. This has security relevance for, for example, the XML_PARSE_NONET flag, if (without it) a custom resource loader accesses the internet and triggers XML external entity injection, SSRF, or a denial of service (e.g., for an attacker-controlled internet resource that is intentionally slow).(CVE-2026-86144)

Severity
6.9 (Medium)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "libxml2-2.11.9-20.oe2403sp1.aarch64.rpm",
          "libxml2-debuginfo-2.11.9-20.oe2403sp1.aarch64.rpm",
          "libxml2-debugsource-2.11.9-20.oe2403sp1.aarch64.rpm",
          "libxml2-devel-2.11.9-20.oe2403sp1.aarch64.rpm",
          "python3-libxml2-2.11.9-20.oe2403sp1.aarch64.rpm"
        ],
        "noarch": [
          "libxml2-help-2.11.9-20.oe2403sp1.noarch.rpm"
        ],
        "src": [
          "libxml2-2.11.9-20.oe2403sp1.src.rpm"
        ],
        "x86_64": [
          "libxml2-2.11.9-20.oe2403sp1.x86_64.rpm",
          "libxml2-debuginfo-2.11.9-20.oe2403sp1.x86_64.rpm",
          "libxml2-debugsource-2.11.9-20.oe2403sp1.x86_64.rpm",
          "libxml2-devel-2.11.9-20.oe2403sp1.x86_64.rpm",
          "python3-libxml2-2.11.9-20.oe2403sp1.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP1",
        "name": "libxml2",
        "purl": "pkg:rpm/openEuler/libxml2\u0026distro=openEuler-24.03-LTS-SP1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.11.9-20.oe2403sp1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Medium"
  },
  "details": "This library allows to manipulate XML files. It includes support to read, modify and write XML and HTML files. There is DTDs support this includes parsing and validation even with complex DtDs, either at parse time or later once the document has been modified. The output can be a simple SAX stream or and in-memory DOM like representations. In this case one can use the built-in XPath and XPointer implementation to select sub nodes or ranges. A flexible Input/Output mechanism is available, with existing HTTP and FTP modules and combined to an URI library.\r\n\r\nSecurity Fix(es):\n\nA flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a `nextCatalog` element lacks its mandatory `catalog` attribute, leading to the application crashing and causing a Denial of Service (DoS).(CVE-2026-76781)\n\nIn libxml2 before 2.15.4, there is a heap-based buffer overflow in xmlXPtrEvalXPtrPart because of xmlXPtrEval xpointer length saturation.(CVE-2026-86142)\n\nIn 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.(CVE-2026-86143)\n\nIn xinclude in libxml2 before 2.15.4, xmlXIncludeProcess and xmlXIncludeProcessTree do not propagate parseFlags. This has security relevance for, for example, the XML_PARSE_NONET flag, if (without it) a custom resource loader accesses the internet and triggers XML external entity injection, SSRF, or a denial of service (e.g., for an attacker-controlled internet resource that is intentionally slow).(CVE-2026-86144)",
  "id": "OESA-2026-4374",
  "modified": "2026-10-16T11:59:55Z",
  "published": "2026-10-16T11:59:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-4374"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76781"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86142"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86143"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86144"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "libxml2 security update",
  "upstream": [
    "CVE-2026-76781",
    "CVE-2026-86142",
    "CVE-2026-86143",
    "CVE-2026-86144"
  ]
}



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