CVE-2026-90157
bpf: Reject negative optlen in cgroup getsockopt hook
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.
INFO
Published Date :
Sept. 17, 2026, 5:17 p.m.
Last Modified :
Sept. 17, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to include the patch.
- Reject negative ctx.optlen in the getsockopt hook.
- Validate optlen bounds in BPF programs.
References to Advisories, Solutions, and Tools
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CVE-2026-90157.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90157 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-90157
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following table lists the changes that have been made to the
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90157.json">CVE-2026-90157</a> Added Reference https://git.kernel.org/stable/c/1b5aacd5b2419b0790e955e466d389a61c79b4b1 Added Reference https://git.kernel.org/stable/c/2bdbe00454200fcb0110f31eeca8d906a3515e74 Added Reference https://git.kernel.org/stable/c/31a89af4f513d750fec196e2bb6195a7d4473e9f Added Reference https://git.kernel.org/stable/c/554ba7195c4108726450e24480c8449990c2268c Added Reference https://git.kernel.org/stable/c/5b09d984b38b018b123c3a9e02a96bbc6468dbe5 Added Reference https://git.kernel.org/stable/c/d02a12b4085ffe41ea750b1007f7a9c7aee2875a Added Reference https://git.kernel.org/stable/c/e6fbf0eba87f50084d67508898f6ad6fc7ff1ba2 Added Reference https://git.kernel.org/stable/c/f68671b1a98d426c57864bd457c125fee14ac1a5