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NVD / CVE Program· CNA Linux

CVE-2026-74282: tipc: prevent snt_unacked underflow on CONN_ACK

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: 0.69% (FIRST EPSS); higher than 52.5% of all records.
  • 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 1e2c956745777e6ffdee7f30da5935741c03ee1e, 3388145d258cf2c4c98278e3987296007d30672e, 3cfa3d8e0dc167850edeb5bf5a07757db83fd54e.

Low priority for now. Upgrade to Linux Linux 1e2c956745777e6ffdee7f30da5935741c03ee1e, 3388145d258cf2c4c98278e3987296007d30672e, 3cfa3d8e0dc167850edeb5bf5a07757db83fd54e 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: tipc: prevent snt_unacked underflow on CONN_ACK tipc_sk_conn_proto_rcv() subtracts the peer-supplied connection ack count from the unsigned 16-bit send counter snt_unacked without checking that it does not exceed the number of messages actually outstanding: tsk->snt_unacked -= msg_conn_ack(hdr); msg_conn_ack() is read straight from a received CONN_MANAGER/CONN_ACK message. If the ack count is larger than snt_unacked, the subtraction wraps to a near-maximum value, leaving tsk_conn_cong() permanently true and starving the connection of further transmits. Validate the ACK count at the start of the CONN_ACK block and drop the message if it acknowledges more messages than are outstanding. A peer (or, for a local connection, the connected peer socket) can otherwise wedge a TIPC connection's send side by sending an oversized connection ack.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 16, 2026
EPSS
0.6% · 52th 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 · 0.6%

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-2026-74282

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

    • 4.7affected
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 3388145d258cf2c4c98278e3987296007d30672eaffected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 67e55b054bf8025658dc0e255057f2a6236416bdaffected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 96f91b8ae1a489b3eca137e7acf42cf985fb8939affected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 47ed873e4ceda34098bd46d8e96b4bb13cad3a04affected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before b44bebdd32c9ff66ee2aebfc317ced44bedd9335affected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 3cfa3d8e0dc167850edeb5bf5a07757db83fd54eaffected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before 1e2c956745777e6ffdee7f30da5935741c03ee1eaffected · git
    • 10724cc7bb7832b482df049c20fd824d928c5eaa and later · before ab3e10b44ba5411779aac7afd2477917dd77750faffected · git
    • before 4.7not 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-2026-74279Aug 15, 2026 · crypto: cavium/cpt - fix DMA cleanup using wrong loop index
    40Plan
  • ← EarlierCVE-2026-74281Aug 15, 2026 · tipc: reject inverted service ranges from peer bindings
    30Monitor
  • Later →CVE-2026-74283Aug 15, 2026 · tipc: require net admin for TIPCv2 netlink mutators
    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 Linux1e2c956745777e6ffdee7f30da5935741c03ee1eVendor (CNA)
Linux Linux3388145d258cf2c4c98278e3987296007d30672eVendor (CNA)
Linux Linux3cfa3d8e0dc167850edeb5bf5a07757db83fd54eVendor (CNA)
Linux Linux47ed873e4ceda34098bd46d8e96b4bb13cad3a04Vendor (CNA)
Linux Linux67e55b054bf8025658dc0e255057f2a6236416bdVendor (CNA)
Linux Linux96f91b8ae1a489b3eca137e7acf42cf985fb8939Vendor (CNA)
Linux Linuxab3e10b44ba5411779aac7afd2477917dd77750fVendor (CNA)
Linux Linuxb44bebdd32c9ff66ee2aebfc317ced44bedd9335Vendor (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

  • 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 (7 more)

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

All records