[17221] in Kerberos-V5-bugs
[krbdev.mit.edu #9247] git commit
daemon@ATHENA.MIT.EDU (Greg Hudson via RT)
Mon Nov 9 12:01:54 2026
From: "Greg Hudson via RT" <rt@krbdev.mit.edu>
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Date: Mon, 09 Nov 2026 12:01:12 -0500
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<URL: https://krbdev.mit.edu/rt/Ticket/Display.html?id=9247 >
Fix RPC leak when client switches from RPCSEC_GSS
svc_do_xprt() currently retains xp_auth across calls for RPCSEC_GSS.
Consequently, there may be a pre-existing xp_auth value when
gssrpc__authenticate() begins. If the client switches to a different
auth flavor, we must destroy the pre-existing xp_auth value or the new
auth handler will overwrite it and leak its contents.
[ghudson@mit.edu: edited commit message and comment]
CVE-2026-112320:
The GSS-RPC transport layer in MIT Kerberos 5 (aka krb5) 1.4 and later
does not release the previous authentication context when a client
switches from an RPCSEC_GSS or AUTH_GSSAPI flavor to a non-GSS flavor
on the same TCP connection. This allows remote attackers to cause a
denial of service (memory exhaustion in kadmind) by repeatedly
establishing and abandoning GSS authentication contexts.
(cherry picked from commit c4288c4a2fd477f60b9390ca5a7db442055e679b)
https://github.com/krb5/krb5/commit/695e8966a6b8750b37f70b0b7d5bc63a221ada07
Author: Julien Rische <jrische@redhat.com>
Committer: Greg Hudson <ghudson@mit.edu>
Commit: 695e8966a6b8750b37f70b0b7d5bc63a221ada07
Branch: krb5-1.22
src/lib/rpc/svc_auth.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
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