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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99156: scsi: st: Fix use-after-free race between st_remove() and st_open()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 00ff1128123d4bdfacd28d68fb4b6e6f657a3648, 18a0e3733ce38718688e813e5e2d1106bd4830e5, 5ef230f734e0d23db007c8405f38b7e226740084; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 00ff1128123d4bdfacd28d68fb4b6e6f657a3648, 18a0e3733ce38718688e813e5e2d1106bd4830e5, 5ef230f734e0d23db007c8405f38b7e226740084; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: scsi: st: Fix use-after-free race between st_remove() and st_open() st_remove() drops the probe reference on the scsi_tape with kref_put() and only afterwards removes its index from st_index_idr. If that was the last reference, scsi_tape_release() frees the structure while it is still published in the idr. scsi_tape_get(), called from st_open(), looks up the tape in st_index_idr and takes a reference under st_ref_mutex and st_index_lock. remove_cdevs() does not wait for opens that are already past chrdev_open(), so an open that is blocked on st_ref_mutex while st_remove() holds it can take the mutex as soon as st_remove() drops it, find the freed tpnt in the idr and call kref_get() on it: BUG: KASAN: slab-use-after-free in st_open Write of size 4 ... st_open (drivers/scsi/st.c:254 drivers/scsi/st.c:1291) chrdev_open ... Freed by task ...: kfree st_remove (drivers/scsi/st.c:4512) Remove the index from the idr before dropping the reference, all under st_ref_mutex. A concurrent scsi_tape_get() now either runs first and holds a valid reference that keeps the tape alive, or runs afterwards and finds nothing, so st_open() fails with -ENXIO. This restores the ordering st_remove() had before the conversion to st_index_idr, where the tape was unpublished from scsi_tapes[] before the final kref_put().

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 28, 2026
Updated
Oct 31, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.7affected
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before 7d7f9d2ee4b0841f3eba9fa3627044ad329428deaffected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before d9517fc39ec3ee13eadefdc17f45300f7d23ed8caffected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before e7a5da4a4820210aa7d7cd8e6eb25aabe9e5b5a7affected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before 00ff1128123d4bdfacd28d68fb4b6e6f657a3648affected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before 5ef230f734e0d23db007c8405f38b7e226740084affected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before a1647b653549ff29f0422a63eabf329b842f3822affected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before 18a0e3733ce38718688e813e5e2d1106bd4830e5affected · git
    • 6c648d95a6af4a79241a916871df17c84c68ea20 and later · before 71caf7f84bd62a4bf91cc95abd2de690afb8d15faffected · git
    • before 3.7not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-99154Oct 28, 2026 · scsi: libiscsi: Reject a negative task index from parse_pdu_itt
    39Monitor
  • ← EarlierCVE-2026-99155Oct 28, 2026 · scsi: xen/scsifront: Check for a NULL shadow entry on a backend response
    0Monitor
  • Later →CVE-2026-99157Oct 28, 2026 · scsi: bsg: Pass reply_len to bsg_setup_queue() to fit UFS ARPMB replies
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux00ff1128123d4bdfacd28d68fb4b6e6f657a3648Vendor (CNA)
Linux Linux18a0e3733ce38718688e813e5e2d1106bd4830e5Vendor (CNA)
Linux Linux5ef230f734e0d23db007c8405f38b7e226740084Vendor (CNA)
Linux Linux71caf7f84bd62a4bf91cc95abd2de690afb8d15fVendor (CNA)
Linux Linux7d7f9d2ee4b0841f3eba9fa3627044ad329428deVendor (CNA)
Linux Linuxa1647b653549ff29f0422a63eabf329b842f3822Vendor (CNA)
Linux Linuxd9517fc39ec3ee13eadefdc17f45300f7d23ed8cVendor (CNA)
Linux Linuxe7a5da4a4820210aa7d7cd8e6eb25aabe9e5b5a7Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 5, 2026+8 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records