5.5

CVE-2025-21857

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]
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Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 6.3 < 6.6.80
Linux ≫ Linux Kernel Version >= 6.7 < 6.12.17
Linux ≫ Linux Kernel Version >= 6.13 < 6.13.5
Linux ≫ Linux Kernel Version6.14 Updaterc1
Linux ≫ Linux Kernel Version6.14 Updaterc2
Linux ≫ Linux Kernel Version6.14 Updaterc3
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.03% 0.095
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
134c704f-9b21-4f2e-91b3-4a467353bcc0 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-476 NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.