CVE-2025-39880

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 its being written to can cause more serious consequences, but luckily its not something that happens often.

Affected Software

References

• https://git.kernel.org/stable/c/23538cfbeed87159a5ac6c61e7a6de3d8d4486a8
• https://git.kernel.org/stable/c/35dbbc3dbf8bccb2d77c68444f42c1e6d2d27983
• https://git.kernel.org/stable/c/591ea9c30737663a471b2bb07b27ddde86b020d5
• https://git.kernel.org/stable/c/6bd8b56899be0b514945f639a89ccafb8f8dfaef
• https://git.kernel.org/stable/c/cdbc9836c7afadad68f374791738f118263c5371
• https://git.kernel.org/stable/c/ea12ab684f8ae8a6da11a22c78d94a79e2163096