{"id":"CVE-2025-68363","title":"bpf: Check skb->transport_header is set in bpf_skb_check_mtu","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check skb->transport_header is set in bpf_skb_check_mtu\n\nThe bpf_skb_check_mtu helper needs to use skb->transport_header when\nthe BPF_MTU_CHK_SEGS flag is used:\n\n\t…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < b3171a5e4622e915e94599a55f4964078bdec27e","Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 97b876fa88322625228792cf7a5fd77531815a80","Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 30ce906557a21adef4cba5901c8e995dc18263a9","Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 1c30e4afc5507f0069cc09bd561e510e4d97fbf7","Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 942268e2726ac7f16e3ec49dbfbbbe7cf5af9da5","Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < d946f3c98328171fa50ddb908593cf833587f725","Linux 5.12"],"published":"2025-12-24","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:43:15.866Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-68363","references":[{"url":"https://git.kernel.org/stable/c/b3171a5e4622e915e94599a55f4964078bdec27e"},{"url":"https://git.kernel.org/stable/c/97b876fa88322625228792cf7a5fd77531815a80"},{"url":"https://git.kernel.org/stable/c/30ce906557a21adef4cba5901c8e995dc18263a9"},{"url":"https://git.kernel.org/stable/c/1c30e4afc5507f0069cc09bd561e510e4d97fbf7"},{"url":"https://git.kernel.org/stable/c/942268e2726ac7f16e3ec49dbfbbbe7cf5af9da5"},{"url":"https://git.kernel.org/stable/c/d946f3c98328171fa50ddb908593cf833587f725"}],"tags":["cve.org"],"epss":0.00207,"epssPercentile":0.096,"ingestedAt":"2026-09-08T15:33:26.996Z","slug":"CVE-2025-68363","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check skb->transport_header is set in bpf_skb_check_mtu\n\nThe bpf_skb_check_mtu helper needs to use skb->transport_header when\nthe BPF_MTU_CHK_SEGS flag is used:\n\n\tbpf_skb_check_mtu(skb, ifindex, &mtu_len, 0, BPF_MTU_CHK_SEGS)\n\nThe transport_header is not always set. There is a WARN_ON_ONCE\nreport when CONFIG_DEBUG_NET is enabled + skb->gso_size is set +\nbpf_prog_test_run is used:\n\nWARNING: CPU: 1 PID: 2216 at ./include/linux/skbuff.h:3071\n skb_gso_validate_network_len\n bpf_skb_check_mtu\n bpf_prog_3920e25740a41171_tc_chk_segs_flag # A test in the next patch\n bpf_test_run\n bpf_prog_test_run_skb\n\nFor a normal ingress skb (not test_run), skb_reset_transport_header\nis performed but there is plan to avoid setting it as described in\ncommit 2170a1f09148 (\"net: no longer reset transport_header in __netif_receive_skb_core()\").\n\nThis patch fixes the bpf helper by checking\nskb_transport_header_was_set(). The check is done just before\nskb->transport_header is used, to avoid breaking the existing bpf prog.\nThe WARN_ON_ONCE is limited to bpf_prog_test_run, so targeting bpf-next.\n\n## Affected\n\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < b3171a5e4622e915e94599a55f4964078bdec27e`\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 97b876fa88322625228792cf7a5fd77531815a80`\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 30ce906557a21adef4cba5901c8e995dc18263a9`\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 1c30e4afc5507f0069cc09bd561e510e4d97fbf7`\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < 942268e2726ac7f16e3ec49dbfbbbe7cf5af9da5`\n- `Linux >= 34b2021cc61642d61c3cf943d9e71925b827941b < d946f3c98328171fa50ddb908593cf833587f725`\n- `Linux 5.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}