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CVE-2026-74262· NVD / CVE Program· CNA Linux

kcm: use WRITE_ONCE() when changing lower socket callbacks

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: 0.18% (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 0cb3e2f40679032c1aa2186280a86e5ead0161ee, 11faefd11ce2448bac7279ab302dd1954a6547fe, 47186409c092cd7dd70350999186c700233e854d.

Low priority for now. Upgrade to Linux Linux 0cb3e2f40679032c1aa2186280a86e5ead0161ee, 11faefd11ce2448bac7279ab302dd1954a6547fe, 47186409c092cd7dd70350999186c700233e854d 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: kcm: use WRITE_ONCE() when changing lower socket callbacks kcm_attach() replaces a live lower TCP socket's sk_data_ready and sk_write_space callbacks with KCM handlers, and kcm_unattach() restores them later. Those callback-pointer updates are still plain stores even though the same fields can be read and invoked concurrently on other CPUs. If another CPU observes an older callback snapshot after the live field has already been restored, callback execution can run with a mismatched target and sk_user_data state, leading to stale or misdirected wakeups. Use WRITE_ONCE() for the callback replacement and restore operations so these shared callback fields follow the same visibility contract already established by the earlier 4022 fixes.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 16, 2026
EPSS
0.1% · 7th 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%

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.

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

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Follow CVE-2026-74262

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

    • 4.6affected
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 0cb3e2f40679032c1aa2186280a86e5ead0161eeaffected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before fa26e4606aed0f7fe793c325506adeda1d847a43affected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before b4ccd6eef671d7c44a30123cd29f3acf3de8468eaffected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before b8c90823cdfb5f3d22f261aeb3e9066612853c36affected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 11faefd11ce2448bac7279ab302dd1954a6547feaffected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before f01fb6138f8eb606b56ce9158e2d8b72352c53f4affected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 9684fff87124b201e11dea01ded9173025359a0faffected · git
    • ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 and later · before 47186409c092cd7dd70350999186c700233e854daffected · git
    • before 4.6not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
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-2026-74260Aug 15, 2026 · netfilter: nf_dup_netdev: add nf_dev_xmit_recursion*() helpers and use them
    31Monitor
  • ← EarlierCVE-2026-74261Aug 15, 2026 · ALSA: seq: avoid stale FIFO cells during resize
    0Monitor
  • Later →CVE-2026-74264Aug 15, 2026 · net: watchdog: fix refcount tracking races
    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 Linux0cb3e2f40679032c1aa2186280a86e5ead0161eeVendor (CNA)
Linux Linux11faefd11ce2448bac7279ab302dd1954a6547feVendor (CNA)
Linux Linux47186409c092cd7dd70350999186c700233e854dVendor (CNA)
Linux Linux9684fff87124b201e11dea01ded9173025359a0fVendor (CNA)
Linux Linuxb4ccd6eef671d7c44a30123cd29f3acf3de8468eVendor (CNA)
Linux Linuxb8c90823cdfb5f3d22f261aeb3e9066612853c36Vendor (CNA)
Linux Linuxf01fb6138f8eb606b56ce9158e2d8b72352c53f4Vendor (CNA)
Linux Linuxfa26e4606aed0f7fe793c325506adeda1d847a43Vendor (CNA)
debian:linux6.1.180-1 · 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).

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. SSVC exploitation— → none
  2. 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