CVE-2026-43458

Kernel crash via stale tty link reference

Published May 8, 2026 · Updated May 8, 2026

Use-after-free in the Linux Kernel CAIF serial driver allows local users to crash the kernel through line-discipline activity. The caif_serial TX path calls tty_write_room() after tty->link can be freed, causing pty_write_room() to dereference the stale tty->link->port pointer. Reachability requires CAP_SYS_ADMIN or CAP_SYS_TTY_CONFIG in the initial user namespace; successful triggering interrupts the host through a kernel crash.

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 the Linux Kernel CAIF serial driver allows local users to crash the kernel through line-discipline activity. The caif_serial TX path calls tty_write_room() after tty->link can be freed, causing pty_write_room() to dereference the stale tty->link->port pointer. Reachability requires CAP_SYS_ADMIN or CAP_SYS_TTY_CONFIG in the initial user namespace; successful triggering interrupts the host through a kernel crash.

The record

CVE
CVE-2026-43458
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=2.6.35
  2. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <23a3ac2e2262a291498567418227b99e1f3606b1
  3. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <27e43356d0defb9fc7fa25265219a3ffeb7b3e98
  4. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <288598d80a068a0e9281de35bcb4ce495f189e2a
  5. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <35b58d3bc716ebb9ebd10fe1cac8c1177242511c
  6. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <52135420e9f75853ea0c6cea7b736e3e98495f7d
  7. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <8460187b4852fd00bd1c76394358053f3fa4d089
  8. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <97a0bb491cae39478c6225381f14e9ac67b7bba7
  9. Affected versionversion=e31d5a05948e4478ba8396063d1e1f39880928e2 <ca2ceba983bb23ea0202c2882d963253416654a3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.35; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <23a3ac2e2262a291498567418227b99e1f3606b1; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <27e43356d0defb9fc7fa25265219a3ffeb7b3e98; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <288598d80a068a0e9281de35bcb4ce495f189e2a; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <35b58d3bc716ebb9ebd10fe1cac8c1177242511c; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <52135420e9f75853ea0c6cea7b736e3e98495f7d; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <8460187b4852fd00bd1c76394358053f3fa4d089; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <97a0bb491cae39478c6225381f14e9ac67b7bba7; version=e31d5a05948e4478ba8396063d1e1f39880928e2 <ca2ceba983bb23ea0202c2882d963253416654a3

Published CVSS scores

7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Amazon LinuxCVSS: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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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