CVE-2026-31536: Linux kernel · smb: server: let send_done handle a completion without IB_SEND_SIGNALED
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% 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:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 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
A fix for this vulnerability has been implemented in the linux-hwe-edge kernel versions listed as affected. Users should update to patched versions to remediate this issue. Since this is a kernel-level vulnerability, applying the official kernel updates from the vendor is the recommended mitigation.
Description
A vulnerability in the Linux kernel's SMB server component related to handling completions without IB_SEND_SIGNALED in smbdirect_send_batch processing has been resolved. This issue could cause improper handling of requests when the connection is broken, potentially leading to unintended signaling of all requests. The vulnerability affects specific versions of the linux-hwe-edge kernel.
References
- ubuntu.com/security/CVE-2026-31536 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-31536 (opens in a new tab)
- git.kernel.org/linus/9da82dc73cb03e85d716a2609364572367a5ff47 (opens in a new tab)
- git.kernel.org/stable/c/24082642654f3e5149913946e89c00a297a8868f (opens in a new tab)
- git.kernel.org/stable/c/9da82dc73cb03e85d716a2609364572367a5ff47 (opens in a new tab)
- git.kernel.org/stable/c/e38b415c024bc3b6321bf8650dbf3f4aab8e74b3 (opens in a new tab)