CVE intelligence and bounded remediation

CVE-2025-11677 — Use After Free in WebSocket server implementation in lws_handshake_serv… security vulnerability

Medium CVSS 6.3

Use After Free in WebSocket server implementation in lws_handshake_server in warmcat libwebsockets may allow an attacker, in specific configurations where the user provides a callback function that handles LWS_CALLBACK_HTTP_CONFIRM_UPGRADE, to achieve denial of service.

Severity
Medium
CVSS
6.3 (4.0)
Published
2025-10-20
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-416

Affected products

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Matched remediation archetype

Use-after-free, double free, and expired resource use

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Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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