bpf: Check skb->transport_header is set in bpf_skb_check_mtu

Summary

CVECVE-2025-68363
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-24 11:15:59 UTC
Updated2026-07-14 13:17:58 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.001730000 probability, percentile 0.069480000 (date 2026-07-14)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b b3171a5e4622e915e94599a55f4964078bdec27e git Not specified
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b 97b876fa88322625228792cf7a5fd77531815a80 git Not specified
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b 30ce906557a21adef4cba5901c8e995dc18263a9 git Not specified
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b 1c30e4afc5507f0069cc09bd561e510e4d97fbf7 git Not specified
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b 942268e2726ac7f16e3ec49dbfbbbe7cf5af9da5 git Not specified
CNA Linux Linux affected 34b2021cc61642d61c3cf943d9e71925b827941b d946f3c98328171fa50ddb908593cf833587f725 git Not specified
CNA Linux Linux affected 5.12 Not specified
CNA Linux Linux unaffected 5.12 semver Not specified
CNA Linux Linux unaffected 6.1.160 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.120 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.63 6.12.* semver Not specified
CNA Linux Linux unaffected 6.17.13 6.17.* semver Not specified
CNA Linux Linux unaffected 6.18.2 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19 * original_commit_for_fix Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified

References

ReferenceSourceLinkTags
cert-portal.siemens.com/productcert/html/ssa-019113.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/30ce906557a21adef4cba5901c8e995dc18263a9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/97b876fa88322625228792cf7a5fd77531815a80 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/942268e2726ac7f16e3ec49dbfbbbe7cf5af9da5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1c30e4afc5507f0069cc09bd561e510e4d97fbf7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d946f3c98328171fa50ddb908593cf833587f725 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b3171a5e4622e915e94599a55f4964078bdec27e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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