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NVD / CVE Program· CNA Linux

CVE-2026-64559: s390/pkey: Check length in PKEY_VERIFYPROTK ioctl

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: 0.12% (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 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7, 693bf91d4db134f9b1c2840c8e287eee3d993bac, 7e7e03848c918aa0acad5ffd75d929e3afec1554.

Low priority for now. Upgrade to Linux Linux 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7, 693bf91d4db134f9b1c2840c8e287eee3d993bac, 7e7e03848c918aa0acad5ffd75d929e3afec1554 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/pkey: Check length in PKEY_VERIFYPROTK ioctl Explicitly check the buffer length request structure provided by user-space and fail, if it exceeds the buffer size.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 29, 2026
Updated
Nov 3, 2026
EPSS
0.1% · 1th percentile

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%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

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.

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-2026-64559

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

    • 6.12affected
    • 8fcc231ce3bea12b78bb94b280cdc03cff342435 and later · before 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7affected · git
    • 8fcc231ce3bea12b78bb94b280cdc03cff342435 and later · before 693bf91d4db134f9b1c2840c8e287eee3d993bacaffected · git
    • 8fcc231ce3bea12b78bb94b280cdc03cff342435 and later · before 7e7e03848c918aa0acad5ffd75d929e3afec1554affected · git
    • 8fcc231ce3bea12b78bb94b280cdc03cff342435 and later · before b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970affected · git
    • before 6.12not affected · semver
    • 6.12.97 and later · up to and including 6.12.*not affected · semver
    • 6.18.40 and later · up to and including 6.18.*not affected · semver
    • 7.1.5 and later · up to and including 7.1.*not affected · semver
    • 7.2 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linux-6.12before 6.12.100-1~deb12u16.12.100-1~deb12u1
Debian:13linuxbefore 6.12.100-16.12.100-1
Debian:14linuxbefore 7.1.5-17.1.5-1

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-2026-64557Jul 29, 2026 · Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()
    35Monitor
  • ← EarlierCVE-2026-64558Jul 29, 2026 · s390/pkey: Check length in pkey_pckmo handler implementation
    31Monitor
  • Later →CVE-2026-64560Jul 29, 2026 · posix-cpu-timers: Prevent UAF caused by non-leader exec() race
    31Monitor

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 Linux0a9e34ccbe772b8f321388cdbdf4f22b94e513e7Vendor (CNA)
Linux Linux693bf91d4db134f9b1c2840c8e287eee3d993bacVendor (CNA)
Linux Linux7e7e03848c918aa0acad5ffd75d929e3afec1554Vendor (CNA)
Linux Linuxb3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970Vendor (CNA)
debian:linux6.12.100-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.100-1~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.

  • CVE-2026-6808210 days apartlibceph: fix two unsafe bare decodes in decode_lockers()
    39Monitor
  • CVE-2026-6816012 days apartceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()
    39Monitor
  • CVE-2026-6838812 days apartsmb/client: handle overlapping allocated ranges in fallocate
    39Monitor
  • CVE-2026-7208417 days apartscsi: target: Bound PR-OUT TransportID parsing to the received buffer
    39Monitor
  • CVE-2026-645512 days apartsctp: validate STALE_COOKIE cause length before reading staleness
    36Monitor
  • CVE-2026-6834312 days apartsmb: client: validate DFS referral PathConsumed
    36Monitor

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).

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)

CWE-125 · Out-of-bounds Read

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.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records