Critical 9.8Published Aug 10, 2026

CVE-2026-68156libceph: refresh auth->authorizer_buf{,_len} after authorizer update

Updated under an hour ago (Oct 27, 2026, 8:50 PM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: libceph: refresh auth->authorizer_buf{,_len} after authorizer update ceph_x_create_authorizer() caches au->buf->vec.iov_base and au->buf->vec.iov_len in struct ceph_auth_handshake. These cached values are then used by the messenger connect code when sending the authorizer. ceph_x_update_authorizer() can rebuild the authorizer when a newer service ticket is available. If the rebuilt authorizer no longer fits in the existing buffer, ceph_x_build_authorizer() drops its reference to au->buf and allocates a new one. If this is the final reference, ceph_buffer_put() frees the old ceph_buffer and its vec.iov_base, but auth->authorizer_buf still points at that freed memory. A subsequent msgr1 reconnect can therefore queue the stale pointer and trigger a KASAN slab-use-after-free in _copy_from_iter() while tcp_sendmsg() copies the authorizer. Refresh auth->authorizer_buf and auth->authorizer_buf_len after a successful authorizer rebuild so the messenger sends the current buffer.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 2334e9997308305ee4fd508fdfe6086c4150ed60; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 79a273df64238a4ade8b709689a78589f755b8ef; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 26f814187abceee90dbb29a02133adb4786fbb13; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 9d37aec9ffe4e743dabc3f84502e9723e17a30d4; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 75e82e8944ac1efe9fdb88bd2f14d9a031282bdf; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 0060ec912292a550198d8d18ac95b433c92a7091; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 5ecfcd5c05866f185357700b81b461dae4f5ebb2; from 0bed9b5c523d577378b6f83eab5835fe30c27208 before 937d61f86d377a3aa578adae7a3dfcecdddf9d89; and 4 more ranges	CNA record

References

References

https://git.kernel.org/stable/c/2334e9997308305ee4fd508fdfe6086c4150ed60
https://git.kernel.org/stable/c/79a273df64238a4ade8b709689a78589f755b8ef
https://git.kernel.org/stable/c/26f814187abceee90dbb29a02133adb4786fbb13
https://git.kernel.org/stable/c/9d37aec9ffe4e743dabc3f84502e9723e17a30d4
https://git.kernel.org/stable/c/75e82e8944ac1efe9fdb88bd2f14d9a031282bdf
https://git.kernel.org/stable/c/0060ec912292a550198d8d18ac95b433c92a7091
https://git.kernel.org/stable/c/5ecfcd5c05866f185357700b81b461dae4f5ebb2
https://git.kernel.org/stable/c/937d61f86d377a3aa578adae7a3dfcecdddf9d89

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.