Bug 2461567 (CVE-2026-31635) - CVE-2026-31635 kernel: rxrpc: fix oversized RESPONSE authenticator length check
Summary: CVE-2026-31635 kernel: rxrpc: fix oversized RESPONSE authenticator length check
Keywords:
Status: NEW
Alias: CVE-2026-31635
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:08 UTC by OSIDB Bzimport
Modified: 2026-04-28 09:59 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-04-24 15:08:52 UTC
In the Linux kernel, the following vulnerability has been resolved:

rxrpc: fix oversized RESPONSE authenticator length check

rxgk_verify_response() decodes auth_len from the packet and is supposed
to verify that it fits in the remaining bytes. The existing check is
inverted, so oversized RESPONSE authenticators are accepted and passed
to rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an
impossible length and hit BUG_ON(len).

Decoded from the original latest-net reproduction logs with
scripts/decode_stacktrace.sh:

RIP: __skb_to_sgvec()
  [net/core/skbuff.c:5285 (discriminator 1)]
Call Trace:
 skb_to_sgvec() [net/core/skbuff.c:5305]
 rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81]
 rxgk_verify_response() [net/rxrpc/rxgk.c:1268]
 rxrpc_process_connection()
   [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364
    net/rxrpc/conn_event.c:386]
 process_one_work() [kernel/workqueue.c:3281]
 worker_thread()
   [kernel/workqueue.c:3353 kernel/workqueue.c:3440]
 kthread() [kernel/kthread.c:436]
 ret_from_fork() [arch/x86/kernel/process.c:164]

Reject authenticator lengths that exceed the remaining packet payload.


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