KEVWire

Security intelligence, with context.

Response snapshot Nov 3, 2026, 22:26 UTC

Back to the wire
Permalink
VulnerabilityCVE-2026-99264

Linux kernel: io_uring/net: don't retry recv on uncommitted buffers

In the Linux kernel, the following vulnerability has been resolved: io_uring/net: don't retry recv on uncommitted buffers Commit 41b70df5b38b ("io_uring/net: commit partial buffers on retry") commits ring provided buffers when a receive is going to be retried after a partial transfer, so that another request using the same buffer group can't be handed the memory the first one keeps receiving into.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-99264 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

io_uring/net: don't retry recv on uncommitted buffers

Commit 41b70df5b38b ("io_uring/net: commit partial buffers on retry") commits ring provided buffers when a receive is going to be retried after a partial transfer, so that another request using the same buffer group can't be handed the memory the first one keeps receiving into. It commits the number of bytes received so far. That does the job for a single buffer which is consumed as a whole, but the request hangs on to all it has mapped:

- For a buffer ring with IOU_PBUF_RING_INC only these bytes are consumed. The rest of the buffer stays at the head of the ring. - For a bundle only the buffers which hold these bytes are consumed, the others that were peeked stay in the ring.

Continue reading

In both cases the next receive with that buffer group gets memory that the retried request is still going to write to, and whoever comes last overwrites the data of the other. What the retry fills isn't committed at all, as the buffer list isn't known any more at that point. So the kernel hands it out again later on, while the CQE tells the application that it was used, and for an incremental buffer that it is done with.

The remainder can't be committed in advance: if the request ends up receiving less, there is no way to tell the application that more was consumed than the CQE accounts for. Complete the request with what it has got instead of retrying it. MSG_WAITALL is no longer honoured for receives into incremental buffers or multi buffer bundles, they can return a short count, with the request marked as failed like for other short MSG_WAITALL transfers.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

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

Not available

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-2026-99264 (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

Cite this record

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

APA

KEVWire. (2026, November 3). Linux kernel: io_uring/net: don't retry recv on uncommitted buffers (CVE-2026-99264). https://kevwire.com/record/CVE-2026-99264

MLA

"Linux kernel: io_uring/net: don't retry recv on uncommitted buffers (CVE-2026-99264)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2026-99264.

Chicago

KEVWire. "Linux kernel: io_uring/net: don't retry recv on uncommitted buffers (CVE-2026-99264)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2026-99264.

Evidence summary (plain text)

Linux kernel: io_uring/net: don't retry recv on uncommitted buffers (Nov 3, 2026).
In the Linux kernel, the following vulnerability has been resolved:

io_uring/net: don't retry recv on uncommitted buffers

Commit 41b70df5b38b ("io_uring/net: commit partial buffers on retry")
commits ring provided buffers when a receive is going to be retried after
a partial transfer, so that another request using the same buffer group
can't be handed the memory the first one keeps receiving into. It commits
the number of bytes received so far.
CVSS 7.8 (version 3.1; evidence as of Nov 3, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-99264).
Sources:
NVD CVE-2026-99264: https://nvd.nist.gov/vuln/detail/CVE-2026-99264
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T19:55:58.742Z&lastModEndDate=2026-11-03T21:25:56.006Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T19:16:00.613Z&lastModEndDate=2026-11-03T20:55:57.138Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-99264.
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: Nov 3, 2026, 21:25 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