CVE-2026-72085

Host denial of service via refcount underflow

Published Aug 15, 2026 · Updated Aug 15, 2026

Denial of service in the Linux kernel Xen pvSCSI backend allows guest OS users to stop a LUN or panic the host via malformed requests. Pre-submission error paths pass a zero-initialized se_cmd to transport_generic_free_cmd(), underflowing cmd_kref and leaking its command tag. A guest with access to a pvSCSI LUN can exhaust the session's tags; panic_on_warn converts the same warning into a host panic.

CVSS severity9.3
Critical
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel Xen pvSCSI backend allows guest OS users to stop a LUN or panic the host via malformed requests. Pre-submission error paths pass a zero-initialized se_cmd to transport_generic_free_cmd(), underflowing cmd_kref and leaking its command tag. A guest with access to a pvSCSI LUN can exhaust the session's tags; panic_on_warn converts the same warning into a host panic.

The record

CVE
CVE-2026-72085
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-911, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <1e97c404e44991fb087c38ccd7414f2d326f9b74
  2. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <9c0f6894982b1f13bda220707497b25ac9c95bdb
  3. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <a13b789497a7fdd27d4d63f5c69d23db706ef0fe
  4. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <ca978f8a93d4d36841839bf2847d29b88c2591d6
  5. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <f1516c56ac540da1769f264c3cfefe4499548a5d
  6. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <fa588f28401102652068c4cc75e135507f4b5106
  7. Affected versionversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45
  8. Affected versionversion=4.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <1e97c404e44991fb087c38ccd7414f2d326f9b74; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <9c0f6894982b1f13bda220707497b25ac9c95bdb; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <a13b789497a7fdd27d4d63f5c69d23db706ef0fe; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <ca978f8a93d4d36841839bf2847d29b88c2591d6; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <f1516c56ac540da1769f264c3cfefe4499548a5d; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <fa588f28401102652068c4cc75e135507f4b5106; version=2dbcdf33dbf61f44b29adb52338282c3d7840d0e <fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45; version=4.6

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
9.3cve.orgCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-911Improper Update of Reference Count
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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