CVE-2026-64543

Kernel memory compromise via premature discoverer free

Published Jul 27, 2026 · Updated Jul 27, 2026

Use-after-free in the Linux Kernel TIPC module allows local users to read or alter kernel memory or crash the system through UDP bearer teardown. bearer_disable() frees the discoverer with kfree() before the deferred UDP cleanup supplies an RCU grace period, while tipc_disc_rcv() still dereferences the object in a receive softirq. Exploitation requires CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP; an unprivileged user namespace can access the permissionless TIPCv2 bearer commands.

CVSS severity7.8
High
EPSS probability0.13%
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 the Linux Kernel TIPC module allows local users to read or alter kernel memory or crash the system through UDP bearer teardown. bearer_disable() frees the discoverer with kfree() before the deferred UDP cleanup supplies an RCU grace period, while tipc_disc_rcv() still dereferences the object in a receive softirq. Exploitation requires CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP; an unprivileged user namespace can access the permissionless TIPCv2 bearer commands.

The record

CVE
CVE-2026-64543
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-825, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 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=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <1579342d71133da7f00daa02c75cebec7372097b
  2. Affected versionversion=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <5e215bf1c47fdddf8203a0fe80a0ed594065f101
  3. Affected versionversion=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2
  4. Affected versionversion=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <b65289e1c3f352a9f92c6e19713ddd647e033253
  5. Affected versionversion=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <ec7d54d8cc1723921d671e3272b427c96366506f
  6. Affected versionversion=4.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <1579342d71133da7f00daa02c75cebec7372097b; version=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <5e215bf1c47fdddf8203a0fe80a0ed594065f101; version=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2; version=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <b65289e1c3f352a9f92c6e19713ddd647e033253; version=25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 <ec7d54d8cc1723921d671e3272b427c96366506f; version=4.17

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Linux 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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-825Expired Pointer Dereference
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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