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NVD / CVE Program· CNA Linux

CVE-2026-80548: s390/vfio_ccw: Selectively expand io_mutex

Noroxi assessment

Priority: Monitor (action score 35/100)

  • 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: 0.12% (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 2a5ac0c0f1f7da33929211a2e41911bf72ee35d8, 2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd, 34f4feff3e90bd09308fad0974e97113b23b812a.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2a5ac0c0f1f7da33929211a2e41911bf72ee35d8, 2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd, 34f4feff3e90bd09308fad0974e97113b23b812a 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: s390/vfio_ccw: Selectively expand io_mutex The io_mutex was defined to serialize the io_regions, but then has also sort of been associated with the I/O themselves because of the close relationship they share. With the handful of races that are possible, the choices are either to: A) expand the scope of io_mutex to close these remaining windows, or B) reduce the scope of io_mutex to just io_region, and introduce a new lock mechanism for the remaining I/O resources This patch implements A, since B brings with it a lot more interactions that would need to be tracked and kept in a correct hierarchy. It also takes advantage of the workqueue element for cp_free() that now gets called out of fsm_notoper(), which could be invoked out of an interrupt context and thus cannot acquire a mutex itself.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Aug 26, 2026
Updated
Oct 16, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.8
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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-80548

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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

    • 5.2affected
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before dab6a6627b0b0cce23653e99c7b0bf8c6cfd82e0affected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before 56d7488533ceac4e986e96e15c9e487a2245bc01affected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before f72a51810d49411bd8cad0c2df8592320a2fe5ccaffected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before 2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cdaffected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before b6aecea4b2b246f9fbd98a5712daa1193a60818eaffected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before 2a5ac0c0f1f7da33929211a2e41911bf72ee35d8affected · git
    • 4f76617378ee97c557b526cb58d3c61eb0a9c963 and later · before 34f4feff3e90bd09308fad0974e97113b23b812aaffected · git
    • before 5.2not affected · semver
    • 5.15.218 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.105-16.12.105-1
Debian:14linuxbefore 7.1.10-17.1.10-1

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-2026-80546Aug 26, 2026 · s390/zcrypt: Improve CCA CPRB length and overflow checks
    31Monitor
  • ← EarlierCVE-2026-80547Aug 26, 2026 · s390/vfio_ccw: Implement a crw lock
    35Monitor
  • Later →CVE-2026-80549Aug 26, 2026 · s390/vfio_ccw: Move cp cleanup out of not operational
    32Monitor

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 Linux2a5ac0c0f1f7da33929211a2e41911bf72ee35d8Vendor (CNA)
Linux Linux2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cdVendor (CNA)
Linux Linux34f4feff3e90bd09308fad0974e97113b23b812aVendor (CNA)
Linux Linux56d7488533ceac4e986e96e15c9e487a2245bc01Vendor (CNA)
Linux Linuxb6aecea4b2b246f9fbd98a5712daa1193a60818eVendor (CNA)
Linux Linuxdab6a6627b0b0cce23653e99c7b0bf8c6cfd82e0Vendor (CNA)
Linux Linuxf72a51810d49411bd8cad0c2df8592320a2fe5ccVendor (CNA)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~deb12u1 · Debian:12Package 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.

No dated events beyond publication.

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

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
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:C/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records