CVE-2025-40271 Affecting kernel-64k-debug-devel-matched package, versions <0:6.12.0-124.31.1.el10_1


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-ROCKY10-KERNEL64KDEBUGDEVELMATCHED-15250079
  • published9 Feb 2026
  • disclosed6 Dec 2025

Introduced: 6 Dec 2025

CVE-2025-40271  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:10 kernel-64k-debug-devel-matched to version 0:6.12.0-124.31.1.el10_1 or higher.
This issue was patched in RLSA-2026:1690.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-debug-devel-matched package and not the kernel-64k-debug-devel-matched package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:10 relevant fixed versions and status.

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

fs/proc: fix uaf in proc_readdir_de()

Pde is erased from subdir rbtree through rb_erase(), but not set the node to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE() set the erased node to EMPTY, then pde_subdir_next() will return NULL to avoid uaf access.

We found an uaf issue while using stress-ng testing, need to run testcase getdent and tun in the same time. The steps of the issue is as follows:

  1. use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current pde is tun3;

  2. in the [time windows] unregister netdevice tun3 and tun2, and erase them from rbtree. erase tun3 first, and then erase tun2. the pde(tun2) will be released to slab;

  3. continue to getdent process, then pde_subdir_next() will return pde(tun2) which is released, it will case uaf access.

CPU 0 | CPU 1

traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2 sys_getdents64() | iterate_dir() | proc_readdir() | proc_readdir_de() | snmp6_unregister_dev() pde_get(de); | proc_remove() read_unlock(&proc_subdir_lock); | remove_proc_subtree() | write_lock(&proc_subdir_lock); [time window] | rb_erase(&root->subdir_node, &parent->subdir); | write_unlock(&proc_subdir_lock); read_lock(&proc_subdir_lock); | next = pde_subdir_next(de); | pde_put(de); | de = next; //UAF |

rbtree of dev_snmp6 | pde(tun3) /
NULL pde(tun2)

CVSS Base Scores

version 3.1