[ CVE-2026-93228 · Published 24 Sep 2026 ]
Vulnerability in Linux
[ Why it matters ]Priority signals
- Critical severity: CVSS 9.1
[ Description ]Official description
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject Write/Reply chunks with segcount 0 A peer can send a Write or Reply chunk whose segcount field is zero. xdr_check_write_chunk() only rejects segcount > rc_maxpages, so zero passes the range check, and xdr_inline_decode(stream, 0) returns the current (non-NULL) cursor without advancing. The function returns true and pcl_alloc_write() then links a struct svc_rdma_chunk with ch_segcount == 0 onto rc_write_pcl or rc_reply_pcl. An earlier patch in this series made pcl_for_each_segment() safe for ch_segcount == 0, so this no longer drives the memory walk it used to. Rejecting the malformed frame at the decode boundary is still worthwhile as defense in depth: it keeps degenerate zero-segment chunks off the parsed chunk lists entirely, so any future consumer that walks ch_segments directly cannot observe one, and it makes the zero-floor easy to backport to trees where the macro change is more intrusive. RFC 8166 has no meaning for a Write/Reply chunk that describes no remote buffer, so no legitimate client is affected. xdr_check_reply_chunk() funnels Reply chunks through xdr_check_write_chunk() and inherits the same rejection. pcl_alloc_write() also links each chunk onto the parsed chunk list before filling its segment array. If a future change weakens the segcount-0 rejection, an incomplete chunk is visible to consumers during the fill loop. Reorder so that list_add_tail() follows the segment fill loop, ensuring only fully-populated chunks appear on the list.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.
[ Advisories ]Government CERT advisories
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CERT-FRCERTFR-2026-AVI-1334
Multiple vulnerabilities in the Red Hat Linux kernel Translated from French
Multiple vulnerabilities have been discovered in the Red Hat Linux kernel. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.
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CERT-FRCERTFR-2026-AVI-1289
Multiple vulnerabilities in the Debian LTS Linux kernel Translated from French
Multiple vulnerabilities have been discovered in the Debian LTS Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.
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CERT-FRCERTFR-2026-AVI-1253
Multiple vulnerabilities in the Debian Linux kernel Translated from French
Multiple vulnerabilities have been discovered in the Debian Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.
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BSI CERT-BundWID-SEC-2026-3579
Linux Kernel: Multiple vulnerabilities Translated from German
[ References ]References
- git.kernel.org/stable/c/28c5a3a572f6cf81ac304459cfd515480995d62a
- git.kernel.org/stable/c/45dbdb2637b7fc5f1355b588780d2a7fb0516805
- git.kernel.org/stable/c/9808eb7656666acc7291bae9ab6b987bd16e47e0
- git.kernel.org/stable/c/a798714b58041e88716db3bf8fb03ae13eecd54a
- git.kernel.org/stable/c/fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f