tipc: prevent snt_unacked underflow on CONN_ACK
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74282
- 2026-10-03 Alias added: GHSA-5xv7-x5qx-3wv4
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-16 Priority changed: LOW → MEDIUM
References
Other 8
- https://git.kernel.org/stable/c/3388145d258cf2c4c98278e3987296007d30672e
- https://git.kernel.org/stable/c/67e55b054bf8025658dc0e255057f2a6236416bd
- https://git.kernel.org/stable/c/96f91b8ae1a489b3eca137e7acf42cf985fb8939
- https://git.kernel.org/stable/c/47ed873e4ceda34098bd46d8e96b4bb13cad3a04
- https://git.kernel.org/stable/c/b44bebdd32c9ff66ee2aebfc317ced44bedd9335
- https://git.kernel.org/stable/c/3cfa3d8e0dc167850edeb5bf5a07757db83fd54e
- https://git.kernel.org/stable/c/1e2c956745777e6ffdee7f30da5935741c03ee1e
- https://git.kernel.org/stable/c/ab3e10b44ba5411779aac7afd2477917dd77750f
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Sources
- CVE-2026-74282 · CVE Program
- CVE-2026-74282 · NVD
- FIRST EPSS
- GHSA-5xv7-x5qx-3wv4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74282 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences