CVE-2026-93228
CVE CVE-2026-93228EUVD EUVD-2026-86233Published 2026-09-24T15:29:10.000ZLast changed 2026-09-25T05:09:48.000ZCVSS 9.1
What the advisory describes
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.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux 5.11; 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 <9808eb7656666acc7291bae9ab6b987bd16e47e0; patch: 0; 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 <a798714b58041e88716db3bf8fb03ae13eecd54a; 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 <45dbdb2637b7fc5f1355b588780d2a7fb0516805; 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 <fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f; patch: 6.12.111; patch: 7.2.4; patch: 7.3-rc1; patch: 6.18.50
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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