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NVD / CVE Program· CNA Linux

CVE-2026-74689: net/atm: fix slab-out-of-bounds read in vcc_setsockopt()

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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 2c5988c7349c0b64a7e0441bfc6e1dca54f7116a, 35f258fee9ed358c6d0f57f91c30bf029c3724af, 6eb6af88710977eb529b558a07294874d8c40c4d; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2c5988c7349c0b64a7e0441bfc6e1dca54f7116a, 35f258fee9ed358c6d0f57f91c30bf029c3724af, 6eb6af88710977eb529b558a07294874d8c40c4d; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1 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: net/atm: fix slab-out-of-bounds read in vcc_setsockopt() vcc_setsockopt() contained an ineffective optlen check: if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname)) return -EINVAL; If __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller passed a mismatched level), the length check optlen != __SO_SIZE(optname) was short-circuited and bypassed. Execution then fell through to switch(optname), calling copy_from_sockptr() assuming optval contained sufficient space. Furthermore, even if level matched, a cgroup BPF setsockopt filter could shrink optlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(), this leads to a KASAN slab-out-of-bounds read when optlen is smaller than the expected structure size. Fix this by using copy_safe_from_sockptr(), which unconditionally validates that optlen is at least the expected size before copying. Also change the local 'value' variable type from 'unsigned long' to 'int' so that SO_SETCLP matches its sizeof(int) ABI encoding on 64-bit systems.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Aug 22, 2026
Updated
Oct 16, 2026
EPSS
0.1% · 3th percentile
CWE
—

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.1
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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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • 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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b3bcd5d65ac03c15787b2a5b36c718e26a689336affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 35f258fee9ed358c6d0f57f91c30bf029c3724afaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6eb6af88710977eb529b558a07294874d8c40c4daffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9f77c1ab382188f5b51982fab6d913443b6dc59faffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2c5988c7349c0b64a7e0441bfc6e1dca54f7116aaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3affected · git
    • before 2.6.12not affected · semver
    • 6.1.183 and later · up to and including 6.1.*not affected · semver
    • 6.6.152 and later · up to and including 6.6.*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 7.1.9-17.1.9-1

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-2026-74687Aug 22, 2026 · watchdog: at91sam9_wdt: prevent timer rearm during teardown
    31Monitor
  • ← EarlierCVE-2026-74688Aug 22, 2026 · sctp: clear control chunk transport if it is being removed
    39Monitor
  • Later →CVE-2026-74690Aug 22, 2026 · s390/ism: Fix UAF of sba and ieq during ism_dev_exit()
    33Monitor

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 Linux2c5988c7349c0b64a7e0441bfc6e1dca54f7116aVendor (CNA)
Linux Linux35f258fee9ed358c6d0f57f91c30bf029c3724afVendor (CNA)
Linux Linux6eb6af88710977eb529b558a07294874d8c40c4dVendor (CNA)
Linux Linux9f77c1ab382188f5b51982fab6d913443b6dc59fVendor (CNA)
Linux Linuxb3bcd5d65ac03c15787b2a5b36c718e26a689336Vendor (CNA)
Linux Linuxd0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.06.6.152.1-1 · Release NotesMicrosoft (MSRC)
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
none
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
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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 (5 more)

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

All records