CVE-2026-74282
Received Received - Intake

Integer Underflow in Linux Kernel TIPC Protocol

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description
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.

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
CVE-2026-74282
EUVD
EUVD-2026-59429

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a flaw in the TIPC (Transparent Inter-Process Communication) protocol where an attacker can manipulate the connection acknowledgment count to cause an underflow in the send counter. This leads to a situation where the connection's send side is permanently blocked, preventing further data transmission.

Detection Guidance

This vulnerability affects the TIPC protocol in the Linux kernel. Detection requires checking for abnormal TIPC connection behavior, such as stalled connections or excessive retransmissions. Monitor kernel logs for TIPC-related errors or warnings using commands like 'dmesg | grep TIPC' or 'journalctl -k | grep TIPC'.

Impact Analysis

If exploited, this vulnerability could allow an attacker to disrupt communication between processes using the TIPC protocol. This could lead to denial of service, where legitimate communication is blocked, or potential data loss if critical processes fail to exchange information.

Mitigation Strategies

Update the Linux kernel to the latest patched version that resolves this issue. If immediate patching is not possible, disable the TIPC module by running 'modprobe -r tipc' or blacklist it in '/etc/modprobe.d/'. Monitor network traffic for suspicious CONN_ACK messages.

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