CVE-2023-52623

Local privilege escalation via unlocked RCU traversal

Published Mar 26, 2024 · Updated Aug 5, 2026

Use-after-free in Linux kernel SUNRPC allows local users to gain kernel privileges through pNFS client I/O on affected releases. The rpc_xprt_switch_has_addr function traverses an RCU-protected transport list without taking rcu_read_lock, allowing concurrent deletion to free rpc_xprt entries while they are read. An unprivileged process needs access to an already-mounted NFSv4.1/pNFS share; successful exploitation enables kernel heap disclosure, memory corruption, control-flow hijacking, or a host panic.

CVSS severity7.8
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel SUNRPC allows local users to gain kernel privileges through pNFS client I/O on affected releases. The rpc_xprt_switch_has_addr function traverses an RCU-protected transport list without taking rcu_read_lock, allowing concurrent deletion to free rpc_xprt entries while they are read. An unprivileged process needs access to an already-mounted NFSv4.1/pNFS share; successful exploitation enables kernel heap disclosure, memory corruption, control-flow hijacking, or a host panic.

The record

CVE
CVE-2023-52623
Published
Mar 26, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <31b62908693c90d4d07db597e685d9f25a120073
  2. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <69c7eeb4f622c2a28da965f970f982db171f3dc6
  3. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <7a96d85bf196c170dcf1b47a82e9bb97cca69aa6
  4. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <8f860c8407470baff2beb9982ad6b172c94f1d0a
  5. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <c430e6bb43955c6bf573665fcebf31694925b9f7
  6. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <e8ca3e73301e23e8c0ac0ce2e6bac4545cd776e0
  7. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <f8cf4dabbdcb8bef85335b0ed7ad5b25fd82ff56
  8. Affected versionversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <fece80a2a6718ed58487ce397285bb1b83a3e54e
  9. Affected versionversion=4.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <31b62908693c90d4d07db597e685d9f25a120073; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <69c7eeb4f622c2a28da965f970f982db171f3dc6; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <7a96d85bf196c170dcf1b47a82e9bb97cca69aa6; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <8f860c8407470baff2beb9982ad6b172c94f1d0a; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <c430e6bb43955c6bf573665fcebf31694925b9f7; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <e8ca3e73301e23e8c0ac0ce2e6bac4545cd776e0; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <f8cf4dabbdcb8bef85335b0ed7ad5b25fd82ff56; version=39e5d2df959dd4aea81fa33d765d2a5cc67a0512 <fece80a2a6718ed58487ce397285bb1b83a3e54e; version=4.9

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

T1068Exploitation for Privilege Escalation

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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