UnratedFix available

rxrpc: Fix missing validation of ticket length in non-XDR key preparsing

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix missing validation of ticket length in non-XDR key preparsing In rxrpc_preparse(), there are two paths for parsing key payloads: the XDR path (for large payloads) and the non-XDR path (for payloads <= 28 bytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly validates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR path fails to do so. This allows an unprivileged user to provide a very large ticket length. When this key is later read via rxrpc_read(), the total token size (toksize) calculation results in a value that exceeds AFSTOKEN_LENGTH_MAX, triggering a WARN_ON(). [ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc] Fix this by adding a check in the non-XDR parsing path of rxrpc_preparse() to ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX, bringing it into parity with the XDR parsing logic.

Products: Kernel
Affected versions: Not specified
Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.12.84, 6.18.25, 6.6.136, 7.0.2
CVEs: CVE-2026-31696
Confirmed fixed CVEs: Not specified
Updated in this feed: 8 Nov 2026, 02:54 UTC · Revision 1

Source evidence

rxrpc: Fix missing validation of ticket length in non-XDR key preparsing

core-osv · Original source

Published 1 May 2026, 13:55 UTC

osv:CVE-2026-31696

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.84, 6.18.25, 7.0.2

Complete source record

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  "url": "https://osv.dev/vulnerability/CVE-2026-31696",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "rxrpc: Fix missing validation of ticket length in non-XDR key preparsing",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix missing validation of ticket length in non-XDR key preparsing In rxrpc_preparse(), there are two paths for parsing key payloads: the XDR path (for large payloads) and the non-XDR path (for payloads <= 28 bytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly validates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR path fails to do so. This allows an unprivileged user to provide a very large ticket length. When this key is later read via rxrpc_read(), the total token size (toksize) calculation results in a value that exceeds AFSTOKEN_LENGTH_MAX, triggering a WARN_ON(). [ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc] Fix this by adding a check in the non-XDR parsing path of rxrpc_preparse() to ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX, bringing it into parity with the XDR parsing logic.",
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      "modified": "2026-10-28T02:30:53.239237049Z",
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  "source_id": "core-osv",
  "document_id": 521985,
  "published_at": "2026-05-01T13:55:57.485+00:00"
}