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CVE-2026-89554 affecting package kernel for versions less than 6.6.157.1-1

Type: advisorySource: OSV1 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 ↗

AZL-100725

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: osv:AZL-100725

kernel

Source reference: /affected/0/package/name

Affected versions
Not stated in this record
Fixed versions
6.6.157.1-1

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "6.6.157.1-1"
          }
        ]
      }
    ],
    "package": {
      "name": "kernel",
      "purl": "pkg:rpm/azure-linux/kernel",
      "ecosystem": "Azure Linux:3"
    },
    "database_specific": {
      "source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100725.json"
    }
  }
]
Related CVEs
CVE-2026-89554

Source reference: /upstream

Publisher severity

No explicit severity was provided.

Linked CVE context

These ratings describe the referenced vulnerabilities and products. They are not a severity rating for every application using this dependency.

CVE-2026-89554 · High

Linux, Linux

Event
#68143 · Revision 1
Added to Heist Feed
Publisher date
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