{
  "cveId": "CVE-2026-31610",
  "url": "https://patchblox.com/security/cve/CVE-2026-31610",
  "summary": "CVE-2026-31610 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-31610, released May 15, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc  The kernel ASN.1 BER decoder calls action callbacks incrementally as it walks the input.  When ksmbd_decode_negTokenInit() reaches the mechToken [2] OCTET STRING element, ksmbd_neg_token_alloc() allocates conn-\u003EmechToken immediately via kmemdup_nul().  If a later element in the same blob is malformed, then the decoder will return nonzero after the allocation is already live.  This could happen if mechListMIC [3] overrunse the enclosing SEQUENCE.  decode_negotiation_token() then sets conn-\u003Euse_spnego = false because both the negTokenInit and negTokenTarg grammars failed.  The cleanup at the bottom of smb2_sess_setup() is gated on use_spnego:  \tif (conn-\u003Euse_spnego \u0026\u0026 conn-\u003EmechToken) { \t\tkfree(conn-\u003EmechToken); \t\tconn-\u003EmechToken = NULL; \t}  so the kfree is skipped, causing the mechToken to never be freed.  This codepath is reachable pre-authentication, so untrusted clients can cause slow memory leaks on a server without even being properly authenticated.  Fix this up by not checking check for use_spnego, as it\u0027s not required, so the memory will always be properly freed.  At the same time, always free the memory in ksmbd_conn_free() incase some other failure path forgot to free it.",
  "published": "2026-04-24T15:16:40Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00136,
  "epssPercentile": 0.03073,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31610",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.180-1",
      "fix": "DEBIAN-CVE-2026-31610",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-31610",
      "released": "2026-05-15T16:01:09Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.85-1",
      "fix": "DEBIAN-CVE-2026-31610",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-31610",
      "released": "2026-05-15T16:01:09Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.19.14-1",
      "fix": "DEBIAN-CVE-2026-31610",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-31610",
      "released": "2026-05-15T16:01:09Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}