KEVWire

Security intelligence, with context.

Response snapshot Oct 30, 2026, 19:11 UTC

Back to the wire
Permalink
VulnerabilityCVE-2026-93228

Linux kernel: svcrdma: Reject Write/Reply chunks with segcount 0

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.

At a glance

Exploited
Not known
Severity
9.1 Critical (CVSS 3.1)
Chance of exploitation
0.5% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-93228 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

9.1

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.5%

Scored Percentile 40.4%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-93228 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-93228, scored 2026-10-30. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Linux kernel: svcrdma: Reject Write/Reply chunks with segcount 0 (CVE-2026-93228). https://kevwire.com/record/CVE-2026-93228

MLA

"Linux kernel: svcrdma: Reject Write/Reply chunks with segcount 0 (CVE-2026-93228)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-93228.

Chicago

KEVWire. "Linux kernel: svcrdma: Reject Write/Reply chunks with segcount 0 (CVE-2026-93228)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-93228.

Evidence summary (plain text)

Linux kernel: svcrdma: Reject Write/Reply chunks with segcount 0 (Sep 24, 2026).
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.
CVSS 9.1 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-93228).
EPSS 0.5% for the following 30 days, scored Oct 30, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-93228&date=2026-10-30).
Sources:
NVD CVE-2026-93228: https://nvd.nist.gov/vuln/detail/CVE-2026-93228
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T13:06:45.042Z&lastModEndDate=2026-10-30T14:50:57.069Z&resultsPerPage=500&startIndex=1000
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T12:22:16.957Z&lastModEndDate=2026-10-30T14:05:57.373Z&resultsPerPage=500&startIndex=1000
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-93228&date=2026-10-30
Record ID: CVE-2026-93228.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 14:52 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

Record JSON

Your account

Email alerts

Email alerts are coming as part of KEVWire Premium: join the waitlist. To follow your stack today, use its RSS feed, which honors your filters, or connect an AI agent through the API.

Suggest an improvement

Ideas, missing sources, corrections, and bugs are all welcome. No account needed. Suggestions are reviewed by a person before anything changes.

Record details

Record detail