seg6: validate SRH length before reading fixed fields
seg6_validate_srh() reads fixed SRH fields such as srh->type and
srh->hdrlen before checking that the supplied length covers the fixed
struct ipv6_sr_hdr fields.
The BPF SEG6 encap path reaches this with a BPF program-supplied pointer
and length: bpf_lwt_push_encap() and the SEG6 local BPF END_B6 and
END_B6_ENCAP actions call bpf_push_seg6_encap(), which forwards the
length to seg6_validate_srh() with no minimum-size guard. A 2-byte SEG6
encap header can therefore make the validator read srh->type at offset 2
beyond the caller-supplied buffer.
Reject lengths shorter than the fixed SRH at the top of
seg6_validate_srh(), before any field is read. This fixes the BPF helper
path and keeps the common validator robust.
Metrics
Affected Vendors & Products
| Source | ID | Title |
|---|---|---|
Ubuntu USN |
USN-8876-1 | Linux kernel (Azure CVM) vulnerabilities |
Ubuntu USN |
USN-8875-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8877-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8878-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8879-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8887-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8888-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8889-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8887-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8888-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8875-2 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8887-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8917-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8918-1 | Linux kernel (Azure) vulnerabilities |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Sat, 17 Oct 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Sat, 22 Aug 2026 05:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 |
Wed, 19 Aug 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-125 | |
| References |
| |
| Metrics |
threat_severity
|
threat_severity
|
Mon, 17 Aug 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 |
Mon, 17 Aug 2026 09:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 CWE-20 |
Mon, 17 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
Sat, 15 Aug 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 CWE-20 |
Sat, 15 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: seg6: validate SRH length before reading fixed fields seg6_validate_srh() reads fixed SRH fields such as srh->type and srh->hdrlen before checking that the supplied length covers the fixed struct ipv6_sr_hdr fields. The BPF SEG6 encap path reaches this with a BPF program-supplied pointer and length: bpf_lwt_push_encap() and the SEG6 local BPF END_B6 and END_B6_ENCAP actions call bpf_push_seg6_encap(), which forwards the length to seg6_validate_srh() with no minimum-size guard. A 2-byte SEG6 encap header can therefore make the validator read srh->type at offset 2 beyond the caller-supplied buffer. Reject lengths shorter than the fixed SRH at the top of seg6_validate_srh(), before any field is read. This fixes the BPF helper path and keeps the common validator robust. | |
| Title | seg6: validate SRH length before reading fixed fields | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-16T18:55:21.670Z
Reserved: 2026-08-09T03:40:39.925Z
Link: CVE-2026-72400
Updated: 2026-10-16T18:48:58.855Z
Status : Received
Published: 2026-08-15T06:22:13.567
Modified: 2026-10-16T19:17:27.930
Link: CVE-2026-72400
OpenCVE Enrichment
Updated: 2026-08-22T07:00:07Z
Ubuntu USN