CVE-2026-31746

Service interruption via leaked AP message allocations

Published May 1, 2026 · Updated May 1, 2026

Memory leak in Linux Kernel allows local users to interrupt service through clear-key RSA requests on s390 CCA accelerators. In the modular-exponentiation and Chinese-remainder-theorem paths in drivers/s390/crypto/zcrypt_msgtype6.c, an older allocation replaces the AP message returned by ap_init_apmsg() without releasing the original allocation. Reachability requires an s390 system using CCA cards as accelerators and authorization to submit the affected clear-key RSA operations.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Linux Kernel allows local users to interrupt service through clear-key RSA requests on s390 CCA accelerators. In the modular-exponentiation and Chinese-remainder-theorem paths in drivers/s390/crypto/zcrypt_msgtype6.c, an older allocation replaces the AP message returned by ap_init_apmsg() without releasing the original allocation. Reachability requires an s390 system using CCA cards as accelerators and authorization to submit the affected clear-key RSA operations.

The record

CVE
CVE-2026-31746
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 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=57db62a130ce69e6f3a870cf1119d8f860391f97 <586222c37d4027dbf60a604fbe820184fee7c1c9
  2. Affected versionversion=57db62a130ce69e6f3a870cf1119d8f860391f97 <ace37bfec3822033e59fff390f2ff99fc96ebe4f
  3. Affected versionversion=57db62a130ce69e6f3a870cf1119d8f860391f97 <c8d46f17c2fc7d25c18e60c008928aecab26184d
  4. Affected versionversion=6.16

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=57db62a130ce69e6f3a870cf1119d8f860391f97 <586222c37d4027dbf60a604fbe820184fee7c1c9; version=57db62a130ce69e6f3a870cf1119d8f860391f97 <ace37bfec3822033e59fff390f2ff99fc96ebe4f; version=57db62a130ce69e6f3a870cf1119d8f860391f97 <c8d46f17c2fc7d25c18e60c008928aecab26184d; version=6.16

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-401Missing Release of Memory after Effective Lifetime
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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