---
id: CVE-2025-39880
title: 'libceph: fix invalid accesses to ceph_connection_v1_info'
summary: |-
  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…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    ea12ab684f8ae8a6da11a22c78d94a79e2163096
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    591ea9c30737663a471b2bb07b27ddde86b020d5
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    23538cfbeed87159a5ac6c61e7a6de3d8d4486a8
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    35dbbc3dbf8bccb2d77c68444f42c1e6d2d27983
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    6bd8b56899be0b514945f639a89ccafb8f8dfaef
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    cdbc9836c7afadad68f374791738f118263c5371
  - Linux 5.11
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-15T21:54:32.238506Z'
published: '2025-09-23'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:32.742Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-39880'
references:
  - url: 'https://git.kernel.org/stable/c/ea12ab684f8ae8a6da11a22c78d94a79e2163096'
  - url: 'https://git.kernel.org/stable/c/591ea9c30737663a471b2bb07b27ddde86b020d5'
  - url: 'https://git.kernel.org/stable/c/23538cfbeed87159a5ac6c61e7a6de3d8d4486a8'
  - url: 'https://git.kernel.org/stable/c/35dbbc3dbf8bccb2d77c68444f42c1e6d2d27983'
  - url: 'https://git.kernel.org/stable/c/6bd8b56899be0b514945f639a89ccafb8f8dfaef'
  - url: 'https://git.kernel.org/stable/c/cdbc9836c7afadad68f374791738f118263c5371'
tags:
  - cve.org
epss: 0.00331
epssPercentile: 0.26082
ingestedAt: '2026-10-15T22:48:25.529Z'
---

## Overview

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.

## Affected

- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < ea12ab684f8ae8a6da11a22c78d94a79e2163096`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 591ea9c30737663a471b2bb07b27ddde86b020d5`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 23538cfbeed87159a5ac6c61e7a6de3d8d4486a8`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 35dbbc3dbf8bccb2d77c68444f42c1e6d2d27983`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 6bd8b56899be0b514945f639a89ccafb8f8dfaef`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < cdbc9836c7afadad68f374791738f118263c5371`
- `Linux 5.11`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.