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.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4476-1 | linux-6.1 security update |
Debian DSA |
DSA-6127-1 | linux security update |
Ubuntu USN |
USN-8094-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8094-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8094-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8094-4 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8094-5 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8152-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8179-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8184-1 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8179-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8185-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8179-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8203-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8204-1 | Linux kernel (Raspberry Pi Real-time) vulnerabilities |
Ubuntu USN |
USN-8185-2 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8179-4 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8258-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8260-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8261-1 | Linux kernel (Xilinx) vulnerabilities |
Ubuntu USN |
USN-8265-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Sun, 11 Jan 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
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Thu, 25 Dec 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Wed, 24 Dec 2025 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | bpf: Check skb->transport_header is set in bpf_skb_check_mtu | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:51:45.485Z
Reserved: 2025-12-16T14:48:05.308Z
Link: CVE-2025-68363
No data.
Status : Deferred
Published: 2025-12-24T11:15:59.720
Modified: 2026-04-15T00:35:42.020
Link: CVE-2025-68363
OpenCVE Enrichment
No data.
No weakness.
Debian DLA
Debian DSA
Ubuntu USN