---
id: CVE-2026-31580
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bcache: fix cached_dev.sb_bio use-after-free and crash

  In our production environment, we have received multiple crash reports
  regarding libceph, which have caught our …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bcache: fix cached_dev.sb_bio use-after-free and crash

  In our production environment, we have received multiple crash reports
  regarding libceph, which have caught our …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 6.6.136
  - 'linux_kernel >= 6.12, < 6.12.83'
  - 'linux_kernel >= 6.13, < 6.18.24'
  - 'linux_kernel >= 6.19, < 6.19.14'
  - 'linux_kernel >= 7.0, < 7.0.1'
patched:
  - linux_kernel 7.0.1
published: '2026-04-24'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:11.713'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31580'
references:
  - url: 'https://git.kernel.org/stable/c/2d6965581e164fa2ba3f7652ddae5535f6336576'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/383f7fec0de8cee1cf7ae1f9d9f14044a61f10f9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/47fa09fe7f3e09df28a51cb2cbd8f5d2f7f6edc1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4f71c8ba2dc009042493021d94a9718fbe2ebf27'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/81f44ed8c3f54abb7561ece774ea4cca5070b2f2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9467d360be70e6ee55b0c1cd2a1f1424f57b5b85'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/add4982510f3b7c318a2dd7438bdc9c63171e753'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f50e7c325ab1207fe941555bcff659f6d7050572'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fec114a98b8735ee89c75216c45a78e28be0f128'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00174
epssPercentile: 0.06409
ingestedAt: '2026-10-15T03:30:12.858Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

bcache: fix cached_dev.sb_bio use-after-free and crash

In our production environment, we have received multiple crash reports
regarding libceph, which have caught our attention:

```
[6888366.280350] Call Trace:
[6888366.280452]  blk_update_request+0x14e/0x370
[6888366.280561]  blk_mq_end_request+0x1a/0x130
[6888366.280671]  rbd_img_handle_request+0x1a0/0x1b0 [rbd]
[6888366.280792]  rbd_obj_handle_request+0x32/0x40 [rbd]
[6888366.280903]  __complete_request+0x22/0x70 [libceph]
[6888366.281032]  osd_dispatch+0x15e/0xb40 [libceph]
[6888366.281164]  ? inet_recvmsg+0x5b/0xd0
[6888366.281272]  ? ceph_tcp_recvmsg+0x6f/0xa0 [libceph]
[6888366.281405]  ceph_con_process_message+0x79/0x140 [libceph]
[6888366.281534]  ceph_con_v1_try_read+0x5d7/0xf30 [libceph]
[6888366.281661]  ceph_con_workfn+0x329/0x680 [libceph]
```

After analyzing the coredump file, we found that the address of
dc->sb_bio has been freed. We know that cached_dev is only freed when it
is stopped.

Since sb_bio is a part of struct cached_dev, rather than an alloc every
time.  If the device is stopped while writing to the superblock, the
released address will be accessed at endio.

This patch hopes to wait for sb_write to complete in cached_dev_free.

It should be noted that we analyzed the cause of the problem, then tell
all details to the QWEN and adopted the modifications it made.

## Affected

- `linux_kernel < 6.6.136`
- `linux_kernel >= 6.12, < 6.12.83`
- `linux_kernel >= 6.13, < 6.18.24`
- `linux_kernel >= 6.19, < 6.19.14`
- `linux_kernel >= 7.0, < 7.0.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.1`