CVE-2026-98442: Linux kernel · net/sched: act_ct: fix helper UAF due to extensions realloc
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 27 Oct 2026, 09:01 UTC
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 18 Oct 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 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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
A fix is available for this vulnerability. Users should apply the official patches or upgrade to fixed kernel versions. Since this is a kernel vulnerability, updating the Linux kernel to a patched version is the recommended mitigation. No additional mitigations are indicated by the vendor advisory.
Description
CVE-2026-98442 is a use-after-free (UAF) vulnerability in the Linux kernel's net/sched subsystem, specifically in the act_ct helper. The issue arises because a raw pointer to the extensions area is stored in an expectations list before all extensions are fully added, and subsequent reallocations can invalidate this pointer. This can lead to invalid memory access when the expectation is later removed. The vulnerability has been fixed by ensuring helpers are called only after all extensions are added.
References
- ubuntu.com/security/CVE-2026-98442 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98442 (opens in a new tab)
- git.kernel.org/stable/c/812c16a255e7773a544e88b39ae6daed25544d30 (opens in a new tab)
- git.kernel.org/stable/c/8988f4d11f3fba0ab38122178836c683ad516a05 (opens in a new tab)
- git.kernel.org/stable/c/dad19b59da050cb60d3f7023dac2a042a84bf0bd (opens in a new tab)
- git.kernel.org/stable/c/1679bbf5fbeac52a310b1a58b2b301bbf388bdbf (opens in a new tab)