In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix WARNING in bpf_tracing_link_release
The trampoline could be corrupted by the blindly
'tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX' in verifier.
- A fexit attached to a tail_call_reachable prog. 'tr->flags' became
'BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX'. And, the
trampoline would poke the target prog's nop insn using jmp insn instead
of call insn.
- Another fexit loaded with the same tail_call_reachable prog target.
'tr->flags' became 'BPF_TRAMP_F_TAIL_CALL_CTX'.
- Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in
'tr->flags', the trampoline will fail to restore the prog's nop insn
using call insn.
[ 3.410719] WARNING: kernel/bpf/syscall.c:3551 at bpf_tracing_link_release+0x53/0x60, CPU#1: test_progs/98
...
[ 3.428793] bpf_link_free+0x58/0x130
[ 3.429293] bpf_link_release+0x23/0x30
Fix the warning by updating 'tr->flags' with '|=' and lock.
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table