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Response snapshot Oct 30, 2026, 17:36 UTC

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VulnerabilityCVE-2026-89530

Linux kernel: svcrdma: Reject inline replies that overflow the pull-up buffer

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject inline replies that overflow the pull-up buffer An RPC-over-RDMA client can request a reply, such as an NFS READ payload, without providing a Write list or a Reply chunk to carry it.

At a glance

Exploited
Not known
Severity
9.8 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-2026-89530 (opens a new tab)

What happened

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

svcrdma: Reject inline replies that overflow the pull-up buffer

An RPC-over-RDMA client can request a reply, such as an NFS READ payload, without providing a Write list or a Reply chunk to carry it. When such a reply needs more scatter/gather entries than the device's Send Queue supports, svc_rdma_pull_up_needed() selects pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole reply into sctxt->sc_xprt_buf.

That buffer is only sc_max_req_size bytes, while the reply on this path is bounded only by the client's request, so svc_rdma_xb_linearize() copies past the end of the buffer and corrupts adjacent slab memory. The oversized length is then stored in sc_sges[0].length and posted, so the device also reads beyond the mapped region.

Continue reading

The SGE-exhaustion branch is the only pull-up path that can exceed the buffer: the threshold branch pulls up only replies smaller than RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE budget are sent directly without linearization. Make svc_rdma_pull_up_needed() report -E2BIG when the reply it would pull up cannot fit sc_max_req_size, and fail the request with ERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping the connection.

The helper no longer answers a simple yes/no question: it now reports pull-up, no pull-up, or -E2BIG for a reply too large to linearize. Rename svc_rdma_pull_up_needed() to svc_rdma_check_pull_up() so its name no longer implies a boolean predicate.

Scores and how they were measured

CVSS base severity

9.8

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/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

0.5%

Scored Percentile 39.7%

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-2026-89530 (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

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-89530, 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 inline replies that overflow the pull-up buffer (CVE-2026-89530). https://kevwire.com/record/CVE-2026-89530

MLA

"Linux kernel: svcrdma: Reject inline replies that overflow the pull-up buffer (CVE-2026-89530)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-89530.

Chicago

KEVWire. "Linux kernel: svcrdma: Reject inline replies that overflow the pull-up buffer (CVE-2026-89530)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-89530.

Evidence summary (plain text)

Linux kernel: svcrdma: Reject inline replies that overflow the pull-up buffer (Sep 11, 2026).
In the Linux kernel, the following vulnerability has been resolved:

svcrdma: Reject inline replies that overflow the pull-up buffer

An RPC-over-RDMA client can request a reply, such as an NFS READ
payload, without providing a Write list or a Reply chunk to carry
it. When such a reply needs more scatter/gather entries than the
device's Send Queue supports, svc_rdma_pull_up_needed() selects
pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole
reply into sctxt->sc_xprt_buf.
CVSS 9.8 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-89530).
EPSS 0.5% for the following 30 days, scored Oct 30, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-89530&date=2026-10-30).
Sources:
NVD CVE-2026-89530: https://nvd.nist.gov/vuln/detail/CVE-2026-89530
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=500
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=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T11:45:59.009Z&lastModEndDate=2026-10-30T13:20:57.281Z&resultsPerPage=500&startIndex=500
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-89530&date=2026-10-30
Record ID: CVE-2026-89530.
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.

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