NULL Pointer Dereference Affecting kernel-debug package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.02% (3rd percentile)

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  • Snyk IDSNYK-CENTOS6-KERNELDEBUG-9447982
  • published15 Mar 2025
  • disclosed12 Mar 2025

Introduced: 12 Mar 2025

CVE-2025-21857  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for Centos:6 kernel-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug package and not the kernel-debug package as distributed by Centos. See How to fix? for Centos:6 relevant fixed versions and status.

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

net/sched: cls_api: fix error handling causing NULL dereference

tcf_exts_miss_cookie_base_alloc() calls xa_alloc_cyclic() which can return 1 if the allocation succeeded after wrapping. This was treated as an error, with value 1 returned to caller tcf_exts_init_ex() which sets exts->actions to NULL and returns 1 to caller fl_change().

fl_change() treats err == 1 as success, calling tcf_exts_validate_ex() which calls tcf_action_init() with exts->actions as argument, where it is dereferenced.

Example trace:

BUG: kernel NULL pointer dereference, address: 0000000000000000 CPU: 114 PID: 16151 Comm: handler114 Kdump: loaded Not tainted 5.14.0-503.16.1.el9_5.x86_64 #1 RIP: 0010:tcf_action_init+0x1f8/0x2c0 Call Trace: tcf_action_init+0x1f8/0x2c0 tcf_exts_validate_ex+0x175/0x190 fl_change+0x537/0x1120 [cls_flower]

CVSS Base Scores

version 3.1