CVE-2023-53189

Kernel crash via IPv6 timer reference underflow

Published Sep 15, 2025 · Updated Sep 15, 2025

Reference-count underflow in affected Linux kernel branches through 6.5-rc1 allows local users to crash the kernel via an IPv6 timer race. addrconf_mod_rs_timer() checks timer_pending() before mod_timer(), so the timer can expire in the gap and addrconf_rs_timer() drops an idev reference that was never acquired. Triggering requires control of IPv6 interface, token, and timer settings through CAP_NET_ADMIN, including within an enabled user and network namespace.

CVSS severity7.8
High
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

Reference-count underflow in affected Linux kernel branches through 6.5-rc1 allows local users to crash the kernel via an IPv6 timer race. addrconf_mod_rs_timer() checks timer_pending() before mod_timer(), so the timer can expire in the gap and addrconf_rs_timer() drops an idev reference that was never acquired. Triggering requires control of IPv6 interface, token, and timer settings through CAP_NET_ADMIN, including within an enabled user and network namespace.

The record

CVE
CVE-2023-53189
Published
Sep 15, 2025
Updated
Sep 15, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-191, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2025Record 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=3.11
  2. Affected versionversion=973d5956f754cfc306f5e274d71503498f4b0324
  3. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <06a0716949c22e2aefb648526580671197151acc
  4. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <1f656e483eb4733d62f18dfb206a49b78f60f495
  5. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <2ad31ce40e8182860b631e37209e93e543790b7c
  6. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <436b7cc7eae7851c184b671ed7a4a64c750b86f7
  7. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <82abd1c37d3bf2a2658b34772c17a25a6f9cca42
  8. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <c6395e32935d35e6f935e7caf1c2dac5a95943b4
  9. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <c7eeba47058532f6077d6a658e38b6698f6ae71a
  10. Affected versionversion=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <df62fdcd004afa72ecbed0e862ebb983acd3aa57

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.11; version=973d5956f754cfc306f5e274d71503498f4b0324; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <06a0716949c22e2aefb648526580671197151acc; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <1f656e483eb4733d62f18dfb206a49b78f60f495; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <2ad31ce40e8182860b631e37209e93e543790b7c; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <436b7cc7eae7851c184b671ed7a4a64c750b86f7; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <82abd1c37d3bf2a2658b34772c17a25a6f9cca42; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <c6395e32935d35e6f935e7caf1c2dac5a95943b4; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <c7eeba47058532f6077d6a658e38b6698f6ae71a; version=b7b1bfce0bb68bd8f6e62a28295922785cc63781 <df62fdcd004afa72ecbed0e862ebb983acd3aa57

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.1Red HatCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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

CWE-191Integer Underflow (Wrap or Wraparound)
T1499Endpoint Denial of Service

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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