CVE-2026-52939

Local denial of service via masked atomic completion

Published Jun 24, 2026 · Updated Jun 24, 2026

NULL pointer dereference in Linux Kernel RDS/InfiniBand allows local users to crash the system via an atomic control message. The rds_ib_send_unmap_op() switch omits masked atomic opcodes, returns a null message pointer, and leaves send->s_op set for rds_ib_send_cqe_handler() to dereference. Triggering requires an unprivileged AF_RDS sendmsg() atomic control message over an active RDS/IB connection and causes an oops or kernel panic.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux Kernel RDS/InfiniBand allows local users to crash the system via an atomic control message. The rds_ib_send_unmap_op() switch omits masked atomic opcodes, returns a null message pointer, and leaves send->s_op set for rds_ib_send_cqe_handler() to dereference. Triggering requires an unprivileged AF_RDS sendmsg() atomic control message over an active RDS/IB connection and causes an oops or kernel panic.

The record

CVE
CVE-2026-52939
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 24, 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=20c72bd5f5f902e5a8745d51573699605bf8d21c <0f22412a2f4fbbe0251c132abee045d15a90e5b6
  2. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <0f7baa82a24813cdad0b06a6f8f07e4824af5ed5
  3. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <34080db3e70ddf94c38512ad2331e3c3afca6cc1
  4. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <4dd262f875e87653df50b138de1390ab0628e6b7
  5. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <4fd34669558085bcb589aa2078a13b0ca79e360d
  6. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <6e4615164d185a26badb2f376a2449f4d174a5f0
  7. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <a0148342badd8c9b2e46551766a27cb76c82e715
  8. Affected versionversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <dcf458120add64c96a6ef5cf719340453f6e6abf
  9. Affected versionversion=2.6.37

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=20c72bd5f5f902e5a8745d51573699605bf8d21c <0f22412a2f4fbbe0251c132abee045d15a90e5b6; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <0f7baa82a24813cdad0b06a6f8f07e4824af5ed5; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <34080db3e70ddf94c38512ad2331e3c3afca6cc1; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <4dd262f875e87653df50b138de1390ab0628e6b7; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <4fd34669558085bcb589aa2078a13b0ca79e360d; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <6e4615164d185a26badb2f376a2449f4d174a5f0; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <a0148342badd8c9b2e46551766a27cb76c82e715; version=20c72bd5f5f902e5a8745d51573699605bf8d21c <dcf458120add64c96a6ef5cf719340453f6e6abf; version=2.6.37

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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