bpf: Check skb->transport_header is set in bpf_skb_check_mtu
In the Linux kernel, the following vulnerability has been resolved:
bpf: Check skb->transport_header is set in bpf_skb_check_mtu
The bpf_skb_check_mtu helper needs to use skb->transport_header when
the BPF_MTU_CHK_SEGS flag is used:
bpf_skb_check_mtu(skb, ifindex, &mtu_len, 0, BPF_MTU_CHK_SEGS)
The transport_header is not always set. There is a WARN_ON_ONCE
report when CONFIG_DEBUG_NET is enabled + skb->gso_size is set +
bpf_prog_test_run is used:
WARNING: CPU: 1 PID: 2216 at ./include/linux/skbuff.h:3071
skb_gso_validate_network_len
bpf_skb_check_mtu
bpf_prog_3920e25740a41171_tc_chk_segs_flag # A test in the next patch
bpf_test_run
bpf_prog_test_run_skb
For a normal ingress skb (not test_run), skb_reset_transport_header
is performed but there is plan to avoid setting it as described in
commit 2170a1f09148 ("net: no longer reset transport_header in __netif_receive_skb_core()").
This patch fixes the bpf helper by checking
skb_transport_header_was_set(). The check is done just before
skb->transport_header is used, to avoid breaking the existing bpf prog.
The WARN_ON_ONCE is limited to bpf_prog_test_run, so targeting bpf-next.
CVE 정보
EPSS
EPSS는 취약점이 악용될 가능성을 예측하는 점수 모델입니다.
EPSS 점수
EPSS 모델은 0과 1(0~100%) 사이의 확률 점수를 생성합니다. 점수가 높을수록 취약점이 악용될 가능성이 높습니다.
날짜
EPSS V0
EPSS V1
EPSS V2 (> 2022-02-04)
EPSS V3 (> 2025-03-07)
EPSS V4 (> 2025-03-17)
2025-12-24
–
–
–
–
0.02%
2025-12-30
–
–
–
–
0.02%
2026-01-12
–
–
–
–
0.03%
2026-01-25
–
–
–
–
0.04%
2026-02-22
–
–
–
–
0.05%
2026-03-29
–
–
–
–
0.05%
2026-04-26
–
–
–
–
0.07%
2026-05-31
–
–
–
–
0.05%
2026-06-07
–
–
–
–
0.07%
EPSS 백분위수
백분위수는 EPSS 점수에 따라 CVE의 순위를 매기는 데 사용됩니다. 예를 들어 EPSS 점수 기준 95번째 백분위수의 CVE는 다른 CVE의 95%보다 악용될 가능성이 높습니다.