CVE-2026-72085: Linux kernel · scsi: xen: scsiback: Free unsubmitted command instead of double-putting it
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.3 Critical · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +43
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 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
Upgrade to a fixed release listed under Affected software.
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 patch is available that fixes the reference count underflow and command tag leak issue. Users should apply the official Linux kernel updates that address this vulnerability. No additional mitigation steps are required beyond applying the vendor-provided fix.
Description
A vulnerability in the Linux kernel's scsi: xen: scsiback component was resolved that involved freeing an unsubmitted command, causing a reference count underflow and potential use-after-free. This flaw could allow a pvSCSI guest to leak command tags of a LUN's session, potentially stopping the LUN or causing a host panic under certain conditions. The issue is fixed by properly freeing the command tag and sending an error response without causing reference count underflow.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72085 (opens in a new tab)
- git.kernel.org/stable/c/1e97c404e44991fb087c38ccd7414f2d326f9b74 (opens in a new tab)
- git.kernel.org/stable/c/9c0f6894982b1f13bda220707497b25ac9c95bdb (opens in a new tab)
- git.kernel.org/stable/c/a13b789497a7fdd27d4d63f5c69d23db706ef0fe (opens in a new tab)
- git.kernel.org/stable/c/ca978f8a93d4d36841839bf2847d29b88c2591d6 (opens in a new tab)
- git.kernel.org/stable/c/f1516c56ac540da1769f264c3cfefe4499548a5d (opens in a new tab)
- git.kernel.org/stable/c/fa588f28401102652068c4cc75e135507f4b5106 (opens in a new tab)
- git.kernel.org/stable/c/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72085 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72085 (opens in a new tab)
- git.kernel.org/linus/ca978f8a93d4d36841839bf2847d29b88c2591d6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)