USN-8910-1 (UBUNTU-CVE-2026-76781)

Vulnerability from osv_ubuntu – Published: 2026-10-08 20:05 – Updated: 2026-10-08 20:05 – Source website
VLAI
Summary
libxml2 vulnerabilities
Details

Yirou Yang discovered that libxml2 incorrectly handled certain XML catalogs. If a user or automated system was tricked into processing a specially crafted XML catalog, an attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service. (CVE-2026-76781)

It was discovered that libxml2 incorrectly handled certain large qualified names, leading to a heap-based buffer overflow. An attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-86138)

It was discovered that libxml2 incorrectly handled escaping certain large URI strings. An attacker could possibly use this issue to cause libxml2 to use excessive resources, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-86139)

Xudong Cao and Meng Xu discovered that libxml2 incorrectly handled certain large XPointer expressions, leading to a heap-based buffer overflow. An attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-86142)

Xudong Cao and Meng Xu discovered that libxml2 did not check for integer overflows before passing output lengths to write callbacks. An attacker could possibly use this issue to cause an application using libxml2 to crash, resulting in a denial of service. (CVE-2026-86143)

It was discovered that libxml2 did not apply parser options, such as disabling network access, when processing XInclude directives under certain circumstances. An attacker could possibly use this issue to perform XML external entity injection or server-side request forgery attacks, or cause a denial of service. (CVE-2026-86144)

References
To clipboard 

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                  "type": "CVSS_V3"
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                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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                },
                {
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                  "type": "Ubuntu"
                }
              ]
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            {
              "id": "CVE-2026-86139",
              "severity": [
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                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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                },
                {
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            {
              "id": "CVE-2026-86142",
              "severity": [
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            {
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          "ecosystem": "Ubuntu:26.04:LTS"
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        "2.14.5+dfsg-0.2",
        "2.14.5+dfsg-0.2build1",
        "2.15.1+dfsg-0.3",
        "2.15.1+dfsg-0.4",
        "2.15.1+dfsg-1",
        "2.15.1+dfsg-2",
        "2.15.1+dfsg-2ubuntu1",
        "2.15.1+dfsg-2ubuntu2",
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        "2.15.2+dfsg-0.1ubuntu0.1",
        "2.15.2+dfsg-0.1ubuntu0.2"
      ]
    }
  ],
  "aliases": [],
  "details": "Yirou Yang discovered that libxml2 incorrectly handled certain XML\ncatalogs. If a user or automated system was tricked into processing a\nspecially crafted XML catalog, an attacker could possibly use this issue to\ncause libxml2 to crash, resulting in a denial of service. (CVE-2026-76781)\n\nIt was discovered that libxml2 incorrectly handled certain large qualified\nnames, leading to a heap-based buffer overflow. An attacker could possibly\nuse this issue to cause libxml2 to crash, resulting in a denial of service,\nor possibly execute arbitrary code. (CVE-2026-86138)\n\nIt was discovered that libxml2 incorrectly handled escaping certain large\nURI strings. An attacker could possibly use this issue to cause libxml2 to\nuse excessive resources, leading to a denial of service. This issue only\naffected Ubuntu 26.04 LTS. (CVE-2026-86139)\n\nXudong Cao and Meng Xu discovered that libxml2 incorrectly handled certain\nlarge XPointer expressions, leading to a heap-based buffer overflow. An\nattacker could possibly use this issue to cause libxml2 to crash, resulting\nin a denial of service, or possibly execute arbitrary code.\n(CVE-2026-86142)\n\nXudong Cao and Meng Xu discovered that libxml2 did not check for integer\noverflows before passing output lengths to write callbacks. An attacker\ncould possibly use this issue to cause an application using libxml2 to\ncrash, resulting in a denial of service. (CVE-2026-86143)\n\nIt was discovered that libxml2 did not apply parser options, such as\ndisabling network access, when processing XInclude directives under certain\ncircumstances. An attacker could possibly use this issue to perform XML\nexternal entity injection or server-side request forgery attacks, or cause\na denial of service. (CVE-2026-86144)",
  "id": "USN-8910-1",
  "modified": "2026-10-08T20:05:15Z",
  "published": "2026-10-08T20:05:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8910-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-76781"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-86138"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-86139"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-86142"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-86143"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-86144"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "libxml2 vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2026-76781",
    "UBUNTU-CVE-2026-86138",
    "UBUNTU-CVE-2026-86139",
    "UBUNTU-CVE-2026-86142",
    "UBUNTU-CVE-2026-86143",
    "UBUNTU-CVE-2026-86144"
  ]
}



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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.