{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "f1bd904175e8190ce14aedee37e207ab51fe3b30"
            },
            {
              "fixed": "9124e078ea2250d8d01d2162a550acb01ef5bf48"
            },
            {
              "fixed": "28069434aef66b9d084f0609b7a29c171846815e"
            },
            {
              "fixed": "36bdd0b45ec3f4822832a56e9db8674c8450dfce"
            },
            {
              "fixed": "9f1e40193eef7f047e6b77cfb4b4cafdecd7a123"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.13.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89761.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix out-of-bounds write when null terminating a label vec\n\naa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE\nis passed. If the components are all distinct no duplicates are dropped,\ndups is 0 and the terminator goes to vec[n], so the caller has to provide\nroom for n + 1 entries.\n\naa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,\ngfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but\nvec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES\nit uses the local array of LOCAL_VEC_ENTRIES pointers, above that it\nallocates exactly len pointers. The terminator therefore lands one entry\npast the end of the local array when len is LOCAL_VEC_ENTRIES, and one\nentry past the end of the allocation when len is larger.\n\nlen comes from the number of \"//\u0026\" separated components in the label name\nand label_count_strn_entries() does not bound it. An unprivileged task\nreaches the parse by writing to /proc/self/attr/apparmor/current or through\nlsm_set_self_attr(2), both of which go through do_setattr(), and the name\nis parsed before the change_profile permission is checked.\nThe query_label() path behind the securityfs .access file, which is\nmode 0666, performs no permission check at all. Every component has to\nresolve to a loaded profile, so a system with policy loaded is required.\n\nThe other two VEC_FLAG_TERMINATE users work on a label vec that\naa_label_alloc() has already sized with \"+ 1 for null terminator entry on\nvec\". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing\nlen + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of\nthe local array and into kzalloc().",
  "id": "CVE-2026-89761",
  "modified": "2026-09-15T03:31:04.885321976Z",
  "published": "2026-09-11T19:47:02.837Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/28069434aef66b9d084f0609b7a29c171846815e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36bdd0b45ec3f4822832a56e9db8674c8450dfce"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9124e078ea2250d8d01d2162a550acb01ef5bf48"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f1e40193eef7f047e6b77cfb4b4cafdecd7a123"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89761.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89761"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "apparmor: fix out-of-bounds write when null terminating a label vec"
}