CVE-2025-39880 libceph: fix invalid accesses to ceph_connection_v1_info
A memory corruption flaw in the Linux kernel's Ceph client allows invalid memory access, potentially causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39880?
CVE-2025-39880 is a critical memory corruption vulnerability in Debian Debian Linux, published on 23 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
libceph: fix invalid accesses to ceph_connection_v1_info
There is a place where generic code in messenger.c is reading and another place where it is writing to con->v1 union member without checking that the union member is active (i.e. msgr1 is in use).
On 64-bit systems, con->v1.auth_retry overlaps with con->v2.out_iter, so such a read is almost guaranteed to return a bogus value instead of 0 when msgr2 is in use. This ends up being fairly benign because the side effect is just the invalidation of the authorizer and successive fetching of new tickets.
con->v1.connect_seq overlaps with con->v2.conn_bufs and the fact that it's being written to can cause more serious consequences, but luckily it's not something that happens often.
Weakness: CWE-704
Which versions are affected by CVE-2025-39880?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39880?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-39880 being exploited?
There is no known exploitation of CVE-2025-39880 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-67662, AZL-74936, BELL-CVE-2025-39880, DEBIAN-CVE-2025-39880, GHSA-f84f-657f-x94w, ROOT-OS-UBUNTU-2204-CVE-2025-39880 and 2 more.