{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7"
            },
            {
              "fixed": "6314089acf0ddf64376fdc0b1420695504c73f52"
            },
            {
              "fixed": "55dc41fe8821e9a849e147255ad572bc933a9d15"
            },
            {
              "fixed": "c424e8519ac78eac5d9f4eecf06208a0d619ec14"
            },
            {
              "fixed": "22d59c72f4a47ffec121d0610f70d0d70c3c11c8"
            },
            {
              "fixed": "eb235472b52ef36981c5aad330485eaf2382c53b"
            },
            {
              "fixed": "179eb62506a02d00370bd6478898cb632e10986c"
            },
            {
              "fixed": "d29abf70c665730e249d2ec8e1402095ae26bcee"
            },
            {
              "fixed": "fc92cdfcb295cefa4344d71a527d61b638b7bfc4"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.1.0"
            },
            {
              "fixed": "5.10.258"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.209"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.175"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.142"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.92"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.34"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64089.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative last_changeset_len\n\nbatadv_piv_tt::last_changeset_len len was declared as s16, but the field is\nnever intended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_data() to allocate a full sized buffer but\npopulates only a small portion of it with the collected changeset. All\nremaining bits are kept uninitialized.\n\nUsing an u16 avoids this type confusion and ensures that no (negative) sign\nextension is performed in batadv_send_my_tt_response().",
  "id": "CVE-2026-64089",
  "modified": "2026-08-13T03:51:52.336197229Z",
  "published": "2026-07-19T15:39:58.729Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64089.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64089"
    },
    {
      "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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "batman-adv: tt: fix negative last_changeset_len"
}