Use After Free Affecting kernel-rt-devel package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (12th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELRTDEVEL-8666891
  • published29 Jan 2025
  • disclosed19 Jan 2025

Introduced: 19 Jan 2025

NewCVE-2025-21633  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-rt-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-devel package and not the kernel-rt-devel package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

io_uring/sqpoll: zero sqd->thread on tctx errors

Syzkeller reports:

BUG: KASAN: slab-use-after-free in thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 Read of size 8 at addr ffff88803578c510 by task syz.2.3223/27552 Call Trace: <TASK> ... kasan_report+0x143/0x180 mm/kasan/report.c:602 thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 thread_group_cputime_adjusted+0xa6/0x340 kernel/sched/cputime.c:639 getrusage+0x1000/0x1340 kernel/sys.c:1863 io_uring_show_fdinfo+0xdfe/0x1770 io_uring/fdinfo.c:197 seq_show+0x608/0x770 fs/proc/fd.c:68 ...

That's due to sqd->task not being cleared properly in cases where SQPOLL task tctx setup fails, which can essentially only happen with fault injection to insert allocation errors.

CVSS Scores

version 3.1