CVE-2025-21857 — NULL Pointer Dereference in Linux
Severity
5.5MEDIUMNVD
EPSS
0.0%
top 89.39%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
Timeline
PublishedMar 12
Latest updateSep 3
Description
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…
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitability: 1.8 | Impact: 3.6