In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject negative optlen in cgroup getsockopt hook

A cgroup getsockopt BPF program can shrink ctx->optlen after the
kernel getsockopt handler has run. The kernel-buffer variant, used by
TCP_ZEROCOPY_RECEIVE, only rejects values larger than the original
length.

If BPF writes a negative optlen, that value is accepted and propagated
back to the TCP getsockopt code. It can then be passed to
copy_to_sockptr() as a size_t and trigger the hardened usercopy
bytes > INT_MAX warning.

Reject negative ctx.optlen in __cgroup_bpf_run_filter_getsockopt_kern(),
matching the lower-bound validation already present in the sockptr-based
getsockopt hook.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4817-1 linux-6.12 security update
Debian DLA Debian DLA DLA-4841-1 linux security update
Debian DSA Debian DSA DSA-6528-1 linux security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sun, 20 Sep 2026 02:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119
CWE-20

Thu, 17 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bpf: Reject negative optlen in cgroup getsockopt hook A cgroup getsockopt BPF program can shrink ctx->optlen after the kernel getsockopt handler has run. The kernel-buffer variant, used by TCP_ZEROCOPY_RECEIVE, only rejects values larger than the original length. If BPF writes a negative optlen, that value is accepted and propagated back to the TCP getsockopt code. It can then be passed to copy_to_sockptr() as a size_t and trigger the hardened usercopy bytes > INT_MAX warning. Reject negative ctx.optlen in __cgroup_bpf_run_filter_getsockopt_kern(), matching the lower-bound validation already present in the sockptr-based getsockopt hook.
Title bpf: Reject negative optlen in cgroup getsockopt hook
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-19T08:58:55.961Z

Reserved: 2026-09-11T19:38:34.790Z

Link: CVE-2026-90157

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-17T17:17:08.817

Modified: 2026-10-19T09:19:05.677

Link: CVE-2026-90157

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-20T02:00:13Z

Weaknesses