CVE-2025-21857

In the Linux kernel, the following vulnerability has been resolved: net/sched: clsapi: fix error handling causing NULL dereference tcfextsmisscookiebasealloc calls xaalloccyclic which can return 1 if the allocation succeeded after wrapping. This was treated as an error, with value 1 returned to...

CVE-2025-21857

CVE-2025-21857 affects the Linux kernel net/sched code (cls_api). The root cause is error handling in tcf_exts_miss_cookie_base_alloc() calling xa_alloc_cyclic() that can return 1 (wraps successfully), which is treated as an error by tcf_exts_init_ex() and causes ext­s to be NULL. fl_change() the...