CVE-2026-68156: Linux kernel · libceph: refresh auth->authorizer_buf{,_len} after authorizer update
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in 2334e9997308305ee4fd508fdfe6086c4150ed60 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in 2334e9997308305ee4fd508fdfe6086c4150ed60, 937d61f86d377a3aa578adae7a3dfcecdddf9d89, 79a273df64238a4ade8b709689a78589f755b8ef +7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
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.
References
- git.kernel.org/stable/c/2334e9997308305ee4fd508fdfe6086c4150ed60 (opens in a new tab)
- git.kernel.org/stable/c/79a273df64238a4ade8b709689a78589f755b8ef (opens in a new tab)
- git.kernel.org/stable/c/26f814187abceee90dbb29a02133adb4786fbb13 (opens in a new tab)
- git.kernel.org/stable/c/9d37aec9ffe4e743dabc3f84502e9723e17a30d4 (opens in a new tab)
- git.kernel.org/stable/c/75e82e8944ac1efe9fdb88bd2f14d9a031282bdf (opens in a new tab)
- git.kernel.org/stable/c/0060ec912292a550198d8d18ac95b433c92a7091 (opens in a new tab)
- git.kernel.org/stable/c/5ecfcd5c05866f185357700b81b461dae4f5ebb2 (opens in a new tab)
- git.kernel.org/stable/c/937d61f86d377a3aa578adae7a3dfcecdddf9d89 (opens in a new tab)