CVE-2026-31665

Kernel memory access via premature timeout free

Published Apr 24, 2026 · Updated Apr 24, 2026

Use-after-free in Linux Kernel Netfilter allows local users to access freed kernel memory during concurrent timeout teardown. nft_ct_timeout_obj_destroy() calls kfree() without an RCU grace period while nf_ct_timeout_data() can retain RCU-protected references. Exploitation requires low local privileges and a race with packet processing; the demonstrated result is an invalid kernel read detected by KASAN.

CVSS severity7.8
High
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

Use-after-free in Linux Kernel Netfilter allows local users to access freed kernel memory during concurrent timeout teardown. nft_ct_timeout_obj_destroy() calls kfree() without an RCU grace period while nf_ct_timeout_data() can retain RCU-protected references. Exploitation requires low local privileges and a race with packet processing; the demonstrated result is an invalid kernel read detected by KASAN.

The record

CVE
CVE-2026-31665
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 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=4.19
  2. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <070abdf1b04325b21a20a2a0c39a2208af107275
  3. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77
  4. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <b42aca3660dc2627a29a38131597ca610dc451f9
  5. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <c458fc1c278a65ad5381083121d39a479973ebed
  6. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <c581e5c8f2b59158f62efe61c1a3dc36189081ff
  7. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <d0983b48c10d1509fd795c155f8b1e832e1369ff
  8. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <f16fe84879a5280f05ebbcea593a189ba0f3e79a
  9. Affected versionversion=7e0b2b57f01d183e1c84114f1f2287737358d748 <f8dca15a1b190787bbd03285304b569631160eda

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.19; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <070abdf1b04325b21a20a2a0c39a2208af107275; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <b42aca3660dc2627a29a38131597ca610dc451f9; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <c458fc1c278a65ad5381083121d39a479973ebed; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <c581e5c8f2b59158f62efe61c1a3dc36189081ff; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <d0983b48c10d1509fd795c155f8b1e832e1369ff; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <f16fe84879a5280f05ebbcea593a189ba0f3e79a; version=7e0b2b57f01d183e1c84114f1f2287737358d748 <f8dca15a1b190787bbd03285304b569631160eda

Published CVSS scores

7.8kernel.orgCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

No sourced classifications are available.

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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