CVE-2026-89968: Linux kernel · nvmet-tcp: reject unsolicited H2CData PDUs
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 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 tracks R2T transmissions and rejects unsolicited H2CData PDUs. Users should apply the official kernel updates that resolve this issue. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's nvmet-tcp subsystem allows a remote unauthenticated attacker to send unsolicited H2CData PDUs. This can cause the same command to be completed twice, leading to a kernel BUG or a soft-lockup in the nvmet_tcp workqueue. The issue arises because the kernel does not verify that the target has solicited the data via an R2T before accepting H2CData PDUs. This flaw has been resolved by tracking R2T transmissions and rejecting unsolicited data PDUs.
References
- ubuntu.com/security/CVE-2026-89968 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89968 (opens in a new tab)
- git.kernel.org/linus/db62b35cbca052860c519cbcabe7650708528738 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89968.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)