CVE-2026-89529

Published Sep 11, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject oversized Read segments at decode time The RPC/RDMA Read list decoder stores wire-supplied segment lengths without validation. xdr_count_read_segments() checks 4-byte alignment for non-zero position values but does not cap the segment length. An oversized rs_length reaches svc_rdma_build_read_segment(), which derives nr_bvec from it and can drive a large dynamic bvec allocation before verifying that enough rq_pages remain. If the post-allocation page-overrun guard fires, the freshly acquired rw context is not returned, leaking the resource. Reject any segment whose length exceeds the receive context's page budget during Read list decoding, consistent with how xdr_check_write_chunk() bounds Write segment counts against rc_maxpages. Also return the rw context on the existing post-allocation overrun path in svc_rdma_build_read_segment(), keeping that defensive guard balanced.

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References

Frequently Asked Questions

What is CVE-2026-89529? +
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject oversized Read segments at decode time The RPC/RDMA Read list decoder stores wire-supplied segment lengths without validation. xdr_count_read_segments() checks 4-byte alignment for non-zero position values but does not cap the segment length. An oversized rs_length reaches svc_rdma_build_read_segment(), which derives nr_bvec from it and can drive a large dynamic bvec allocation before verifying that enough rq_pages remain. If the post-allocation page-overrun guard fires, the freshly acquired rw context is not returned, leaking the resource. Reject any segment whose length exceeds the receive context's page budget during Read list decoding, consistent with how xdr_check_write_chunk() bounds Write segment counts against rc_maxpages. Also return the rw context on the existing post-allocation overrun path in svc_rdma_build_read_segment(), keeping that defensive guard balanced.
How do I check if I'm vulnerable to CVE-2026-89529? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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