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NVD / CVE Program· CNA Linux

CVE-2026-74696: tcp: fix TFO max_qlen accounting across reuseport migration

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.49% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 585fc5247d14939a561056aa2addd9b7c2b1f670, 6e10ee56524a26b250229ad348637825646ddb88, a0ab2ba83e35159d81cec830a92e885ecf8139be; 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 585fc5247d14939a561056aa2addd9b7c2b1f670, 6e10ee56524a26b250229ad348637825646ddb88, a0ab2ba83e35159d81cec830a92e885ecf8139be; 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: tcp: fix TFO max_qlen accounting across reuseport migration A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through far more pending Fast Open requests than it was configured for. This only shows up with SO_REUSEPORT listener migration, where closing a listener hands its still-pending TFO children over to a surviving one. fastopenq.qlen is charged in tcp_fastopen_create_child() when the child is created and uncharged in reqsk_fastopen_remove() when the handshake completes. The uncharge follows rsk_listener of the request the child points at, and inet_reqsk_clone() has repointed the child at a new request owned by the new listener, so the ++ and the -- land on two different sockets. The new listener's qlen drifts negative and its limit no longer binds. Charge the new listener during migration, like reqsk_queue_migrated() already does for queue->young and queue->qlen.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 22, 2026
Updated
Oct 16, 2026
EPSS
0.4% · 42th percentile
CWE
—

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.5
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-2026-74696

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

    • 5.14affected
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before e98f0d80b9cccb5f828425d2004f9686e7d1ae24affected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before b6247e0f96bd825ffb2005257f6177b5e642dee6affected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before 585fc5247d14939a561056aa2addd9b7c2b1f670affected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before 6e10ee56524a26b250229ad348637825646ddb88affected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before a66e869cf0c90c1e47ae75f72b6482acbfc808ffaffected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before d974618b2097453778389d385e3741629c40e0a3affected · git
    • 54b92e84193749c9968aff2dd46e3b0f42643e18 and later · before a0ab2ba83e35159d81cec830a92e885ecf8139beaffected · git
    • before 5.14not affected · semver
    • 5.15.216 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 7.1.9-17.1.9-1

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-2026-74694Aug 22, 2026 · net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length
    0Monitor
  • ← EarlierCVE-2026-74695Aug 22, 2026 · netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref()
    30Monitor
  • Later →CVE-2026-74697Aug 22, 2026 · bnxt_en: Disable EOP for TPA on all chips to prevent data corruption
    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 Linux585fc5247d14939a561056aa2addd9b7c2b1f670Vendor (CNA)
Linux Linux6e10ee56524a26b250229ad348637825646ddb88Vendor (CNA)
Linux Linuxa0ab2ba83e35159d81cec830a92e885ecf8139beVendor (CNA)
Linux Linuxa66e869cf0c90c1e47ae75f72b6482acbfc808ffVendor (CNA)
Linux Linuxb6247e0f96bd825ffb2005257f6177b5e642dee6Vendor (CNA)
Linux Linuxd974618b2097453778389d385e3741629c40e0a3Vendor (CNA)
Linux Linuxe98f0d80b9cccb5f828425d2004f9686e7d1ae24Vendor (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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 (6 more)

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

All records