CVE-2026-89533Network attack vector

Excessive kernel allocation via svcrdma length underflow

Published Sep 11, 2026 · Updated Sep 11, 2026

Integer underflow in the Linux svcrdma server allows attackers to trigger excessive kernel allocation via crafted RPC-over-RDMA Read chunks. The svc_rdma_read_chunk_range() loop mishandles a segment-boundary offset and subtracts the offset after applying the length cap, producing a near-UINT_MAX DMA length that reaches kmalloc_array_node(). The NFS/RDMA server must be enabled and reachable; successful triggering consumes multi-megabyte kernel allocations, while a crash or reboot is not established.

CVSS severityUnavailable
Unscored
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in the Linux svcrdma server allows attackers to trigger excessive kernel allocation via crafted RPC-over-RDMA Read chunks. The svc_rdma_read_chunk_range() loop mishandles a segment-boundary offset and subtracts the offset after applying the length cap, producing a near-UINT_MAX DMA length that reaches kmalloc_array_node(). The NFS/RDMA server must be enabled and reachable; successful triggering consumes multi-megabyte kernel allocations, while a crash or reboot is not established.

The record

CVE
CVE-2026-89533
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.11
  2. Affected versionversion=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4493c96bbd0068fadf69cbae8d13426202e34cdc
  3. Affected versionversion=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e
  4. Affected versionversion=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <6ee4dc7476b3abc92ec1d444533a559f33f59561
  5. Affected versionversion=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <a46b35f213c2426f5d6a0458a8f7e873fc59cdfd

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.11; version=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4493c96bbd0068fadf69cbae8d13426202e34cdc; version=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e; version=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <6ee4dc7476b3abc92ec1d444533a559f33f59561; version=d7cc73972661be4a02a1b09f1d9b3283c6c05154 <a46b35f213c2426f5d6a0458a8f7e873fc59cdfd

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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