CVE-2026-90157

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References