CVE-2026-43458: Linux kernel · serial: caif: hold tty->link reference in ldisc_open and ser_release
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · patch available : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@7.0.0-1008.8?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available and should be applied to affected Linux kernel versions. The fix involves holding an extra reference on tty->link to prevent the use-after-free. Users should update to patched kernel versions as per the vendor advisory. No additional mitigation steps are indicated by the vendor.
Description
A use-after-free vulnerability in the Linux kernel's caif serial driver was resolved by holding an extra reference on tty->link during the lifetime of the caif_serial line discipline. This prevents a KASAN slab-use-after-free triggered in pty_write_room() when caif_serial's TX path calls tty_write_room(). The issue affects specific Linux kernel versions and has been patched.
References
- ubuntu.com/security/CVE-2026-43458 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43458 (opens in a new tab)
- git.kernel.org/linus/288598d80a068a0e9281de35bcb4ce495f189e2a (opens in a new tab)
- git.kernel.org/stable/c/23a3ac2e2262a291498567418227b99e1f3606b1 (opens in a new tab)
- git.kernel.org/stable/c/27e43356d0defb9fc7fa25265219a3ffeb7b3e98 (opens in a new tab)
- git.kernel.org/stable/c/288598d80a068a0e9281de35bcb4ce495f189e2a (opens in a new tab)
- git.kernel.org/stable/c/35b58d3bc716ebb9ebd10fe1cac8c1177242511c (opens in a new tab)
- git.kernel.org/stable/c/52135420e9f75853ea0c6cea7b736e3e98495f7d (opens in a new tab)
- git.kernel.org/stable/c/8460187b4852fd00bd1c76394358053f3fa4d089 (opens in a new tab)
- git.kernel.org/stable/c/97a0bb491cae39478c6225381f14e9ac67b7bba7 (opens in a new tab)
- git.kernel.org/stable/c/ca2ceba983bb23ea0202c2882d963253416654a3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)