Time-of-check Time-of-use (TOCTOU) Affecting perf6.18-debuginfo package, versions <1:6.18.25-55.108.amzn2023


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.01% (4th percentile)

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  • Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-16737833
  • published18 May 2026
  • disclosed24 Apr 2026

Introduced: 24 Apr 2026

CVE-2026-31580  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.25-55.108.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1693.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1