CVE-2026-68156
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.
CSIRTS triage
- What
- The Ceph authentication authorizer buffer is not refreshed after update, allowing stale authentication credentials to be used.
- Who is affected
- Linux systems running libceph with Ceph cluster authentication enabled.
- Urgency
- Medium priority; authentication bypass weakens security posture but requires active Ceph cluster interaction.
- Action
- Apply Linux kernel patch that refreshes auth->authorizer_buf after authorizer update in libceph.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch CVE-2026-68156
Get an email if CVE-2026-68156 is added to CISA KEV, gains public exploit code, or a new advisory cites it — max one per day, one-click unsubscribe.
Exploitation outlook
- Low exploitation risk0.68% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 50% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
Embed the live status
— this badge updates automatically when the KEV or exploit status changes. How to embed it →
[](https://www.csirts.com/cve/CVE-2026-68156)