Linux Kernel up to 7.2-rc3 scsiback scsiback_do_cmd_fn use after free

CVSS Meta Temp Score
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CTI Interest Score
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3.7$0-$5k0.93+

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2-rc3. It has been declared as problematic. Affected by this issue is the function scsiback_do_cmd_fn of the component scsiback. Executing a manipulation can lead to use after free. The identification of this vulnerability is CVE-2026-72085. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.2-rc3 and classified as problematic. This vulnerability affects the function scsiback_do_cmd_fn of the component scsiback. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: scsi: xen: scsiback: Free unsubmitted command instead of double-putting it scsiback_get_pend_req() obtains a command tag and returns a vscsibk_pend whose embedded se_cmd has only been memset to 0, so its cmd_kref is 0; the se_cmd is initialised (kref_init() via target_init_cmd()) only later, in scsiback_cmd_exec(), on the successful VSCSIIF_ACT_SCSI_CDB path. The two error paths in scsiback_do_cmd_fn() taken before the command is submitted -- a failed scsiback_gnttab_data_map() and an unknown ring_req.act -- call transport_generic_free_cmd(&pending_req->se_cmd, 0), which kref_put()s a refcount of 0. That underflows it ("refcount_t: underflow; use-after-free") and, as the release function is not run, leaks the command tag. Impact: a pvSCSI guest can leak every command tag of a LUN's session, stopping the LUN, by submitting requests with a bad grant reference or an unknown request type; under panic_on_warn the refcount underflow panics the host. Add a helper that just returns the tag with target_free_tag() and sends the error response. It frees the tag while the v2p reference still pins the session, and snapshots the response fields beforehand because freeing the tag can let another ring reuse the pending_req slot.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-72085 since 08/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are needed for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/15/2026).

Upgrading to version 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc4 eliminates this vulnerability. Applying the patch 9c0f6894982b1f13bda220707497b25ac9c95bdb/a13b789497a7fdd27d4d63f5c69d23db706ef0fe/fa588f28401102652068c4cc75e135507f4b5106/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45/f1516c56ac540da1769f264c3cfefe4499548a5d/1e97c404e44991fb087c38ccd7414f2d326f9b74/ca978f8a93d4d36841839bf2847d29b88c2591d6 is able to eliminate this problem.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.8
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.8
VulDB Temp Score: 3.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.212/6.1.178/6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc4
Patch: 9c0f6894982b1f13bda220707497b25ac9c95bdb/a13b789497a7fdd27d4d63f5c69d23db706ef0fe/fa588f28401102652068c4cc75e135507f4b5106/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45/f1516c56ac540da1769f264c3cfefe4499548a5d/1e97c404e44991fb087c38ccd7414f2d326f9b74/ca978f8a93d4d36841839bf2847d29b88c2591d6

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72085 (🔒)
GCVE (CVE): GCVE-0-2026-72085
GCVE (VulDB): GCVE-100-390424

Entryinfo

Created: 08/15/2026 11:08
Changes: 08/15/2026 11:08 (59)
Complete: 🔍
Cache ID: 216::103

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