CVE-2023-52499

Local kernel crash via misdirected syscall return

Published Mar 2, 2024 · Updated May 11, 2026

A syscall-return flaw in Linux allows local users on PowerPC 47x systems to crash the kernel during an instruction-cache flush. In ret_from_syscall, the icache_44x_need_flush path branches to the wrong reused numeric label, so rfi restores bogus register values instead of returning safely to userspace. The condition requires the PowerPC 47x path and an out-of-line cache flush; the demonstrated consequence is an instruction-fetch fault and kernel crash.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A syscall-return flaw in Linux allows local users on PowerPC 47x systems to crash the kernel during an instruction-cache flush. In ret_from_syscall, the icache_44x_need_flush path branches to the wrong reused numeric label, so rfi restores bogus register values instead of returning safely to userspace. The condition requires the PowerPC 47x path and an out-of-line cache flush; the demonstrated consequence is an instruction-fetch fault and kernel crash.

The record

CVE
CVE-2023-52499
Published
Mar 2, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 2, 2024CVE publishedPublication date reported by the CVE source.
  2. May 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=5.12
  2. Affected versionversion=6f76a01173ccaa363739f913394d4e138d92d718 <29017ab1a539101d9c7bec63cc13a019f97b2820
  3. Affected versionversion=6f76a01173ccaa363739f913394d4e138d92d718 <70f6756ad96dd70177dddcfac2fe4bd4bb320746
  4. Affected versionversion=6f76a01173ccaa363739f913394d4e138d92d718 <8ac2689502f986a46f4221e239d4ff2897f1ccb3
  5. Affected versionversion=6f76a01173ccaa363739f913394d4e138d92d718 <f0eee815babed70a749d2496a7678be5b45b4c14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=6f76a01173ccaa363739f913394d4e138d92d718 <29017ab1a539101d9c7bec63cc13a019f97b2820; version=6f76a01173ccaa363739f913394d4e138d92d718 <70f6756ad96dd70177dddcfac2fe4bd4bb320746; version=6f76a01173ccaa363739f913394d4e138d92d718 <8ac2689502f986a46f4221e239d4ff2897f1ccb3; version=6f76a01173ccaa363739f913394d4e138d92d718 <f0eee815babed70a749d2496a7678be5b45b4c14

Published CVSS scores

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

T1499Endpoint Denial of Service

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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