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apparmor: fix out-of-bounds write when null terminating a label vec

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix out-of-bounds write when null terminating a label vec aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE is passed. If the components are all distinct no duplicates are dropped, dups is 0 and the terminator goes to vec[n], so the caller has to provide room for n + 1 entries. aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len, gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it allocates exactly len pointers. The terminator therefore lands one entry past the end of the local array when len is LOCAL_VEC_ENTRIES, and one entry past the end of the allocation when len is larger. len comes from the number of "//&" separated components in the label name and label_count_strn_entries() does not bound it. An unprivileged task reaches the parse by writing to /proc/self/attr/apparmor/current or through lsm_set_self_attr(2), both of which go through do_setattr(), and the name is parsed before the change_profile permission is checked. The query_label() path behind the securityfs .access file, which is mode 0666, performs no permission check at all. Every component has to resolve to a loaded profile, so a system with policy loaded is required. The other two VEC_FLAG_TERMINATE users work on a label vec that a

Announced Source revision 1
Original source ↗

CVE-2026-89761

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-89761

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30",
        "lessThan": "b17c8f5dcb36a032688847b2bce4bd813b4baad1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30",
        "lessThan": "9124e078ea2250d8d01d2162a550acb01ef5bf48",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30",
        "lessThan": "28069434aef66b9d084f0609b7a29c171846815e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30",
        "lessThan": "36bdd0b45ec3f4822832a56e9db8674c8450dfce",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f1bd904175e8190ce14aedee37e207ab51fe3b30",
        "lessThan": "9f1e40193eef7f047e6b77cfb4b4cafdecd7a123",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "security/apparmor/include/label.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.13"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.13",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.109",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.50",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "security/apparmor/include/label.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-89761

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#46723 · Revision 1
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Publisher date
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