CVE-2026-98441: Linux kernel · net/sched: act_ct: avoid modifying shared unconfirmed ct entry
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 27 Oct 2026, 09:02 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 that resets the unconfirmed connection tracking entry to avoid unsafe sharing and modification. Users should apply the official patches or upgrade to fixed kernel versions to remediate this vulnerability. Since this is a kernel-level issue, updating the Linux kernel to a version that includes the fix is the recommended mitigation. No additional workarounds or mitigations are indicated.
Description
CVE-2026-98441 is a high-severity vulnerability in the Linux kernel's net/sched act_ct module. It involves improper handling of shared unconfirmed connection tracking (ct) entries when skb packets are cloned. This can lead to use-after-free (UAF) conditions due to modification of shared unconfirmed ct entries, potentially causing system crashes or other impacts. The issue arises when multiple clones of an skb with an unconfirmed ct entry are processed with different extension sets, breaking pointers in the expectation list. The vulnerability affects specific Linux kernel versions and has been addressed by resetting the ct entry to avoid unsafe sharing and modification.
References
- ubuntu.com/security/CVE-2026-98441 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98441 (opens in a new tab)
- git.kernel.org/stable/c/b097d9d7a5b09c8ec5c4c1a08e35ac5a66b06b44 (opens in a new tab)
- git.kernel.org/stable/c/2b783c562c3238ff50c34fd7a72a735c9cc73d9a (opens in a new tab)
- git.kernel.org/stable/c/4a04ed91575819fb1859311113e95700b709bec7 (opens in a new tab)
- git.kernel.org/stable/c/f85009dfcd65e5969526b0db7a49b5413746e630 (opens in a new tab)