--- id: CVE-2026-93228 title: |- 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 >… summary: |- 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 >… severity: critical cvss: 9.1 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H' vendor: Linux product: Linux affected: - >- Linux >= 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 < fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f - >- Linux >= 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 < a798714b58041e88716db3bf8fb03ae13eecd54a - >- Linux >= 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 < 45dbdb2637b7fc5f1355b588780d2a7fb0516805 - >- Linux >= 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2 < 9808eb7656666acc7291bae9ab6b987bd16e47e0 - Linux 5.11 published: '2026-09-24' updated: '2026-09-25' sourceUpdated: '2026-09-25T05:17:00.567' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93228' references: - url: 'https://git.kernel.org/stable/c/45dbdb2637b7fc5f1355b588780d2a7fb0516805' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/9808eb7656666acc7291bae9ab6b987bd16e47e0' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/a798714b58041e88716db3bf8fb03ae13eecd54a' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93228.json - url: 'https://access.redhat.com/security/cve/CVE-2026-93228' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2540230' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93228' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93228' - url: >- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93228.mbox - url: 'https://access.redhat.com/errata/RHSA-2026:83207' - url: 'https://access.redhat.com/errata/RHSA-2026:83156' - url: 'https://access.redhat.com/errata/RHSA-2026:83157' - url: 'https://access.redhat.com/errata/RHSA-2026:83159' - url: 'https://git.kernel.org/stable/c/28c5a3a572f6cf81ac304459cfd515480995d62a' tags: - nvd - cve.org - csaf - vex - red-hat - score-dispute ingestedAt: '2026-09-24T15:45:56.662Z' epss: 0.00467 epssPercentile: 0.40247 cwe: - CWE-839 scores: nvd: 9.1 vendor: 5.5 cna: 9.1 patched: - 10base_smtv - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_hidden_v_10 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 --- ## Overview 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. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93228.json) - **RHSA-2026:83207** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:83207) - **RHSA-2026:83156** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83156) - **RHSA-2026:83157** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83157) - **RHSA-2026:83159** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83159)