Skip to content
Heist/ feed
High

mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction mptcp_token_join_cookie_init_state() restores remote_nonce, local_nonce, backup, join_id, token and msk from the saved cookie entry when rebuilding the request socket for a MP_JOIN 4th-ACK handled under SYN cookies, but it does not restore local_id, even though the SYN path saved it. subflow_ulp_clone() then reads that uninitialized field and stores it as the joined subflow's address-ID. Because the request-sock slab is SLAB_TYPESAFE_BY_RCU and not zeroed on allocation, the value is the stale byte of a previously freed request socket, which an off-path peer can influence by sending concurrent MP_JOIN SYNs. This corrupts the path manager's id-based subflow bookkeeping for the connection. Restore subflow_req->local_id from the cookie entry, as done for the other fields.

Announced Source revision 1
Original source ↗

CVE-2026-89554

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-2026-89554

Linux

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

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

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": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "4534e0eead692bb069ad1e6a5a245fc2e2078300",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "63cacb05e51a1c6e1349d2e593d00fd6ef43def4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "954b5ea836eb118d188975ced803448537ab8479",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "9df36a4846375a9b75bf42d77bfed216b0f366f9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "64f2c5dd49b956a542c8c02b8dad5d262a462bba",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "51887ccd88791ddaa8755a7c614fda031ecf7982",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "bf19d166337c6488b39cb03eeeffb30a941d6326",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9466a1ccebbe54ac57fb8a89c2b4b854826546a8",
        "lessThan": "b878dfdd12d7a5b8722a78d35e313506140ca3d9",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/mptcp/syncookies.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.9"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.9",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.270",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "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": [
      "net/mptcp/syncookies.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-89554

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#35069 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement