CVE-2026-74752
Received Received - Intake

SCTP Cookie Authentication State Validation Flaw

Publication date: 2026-08-26

Last updated on: 2026-08-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: sctp: validate cookie AUTH state before use When cookie authentication is disabled, COOKIE_ECHO restores fixed-size AUTH fields directly from peer-controlled cookie bytes. A forged RANDOM length, HMAC list, or CHUNKS list can then reach association consumers with lengths or identifiers that were never validated against the local backing arrays. A forged RANDOM length can cause out-of-bounds reads during key-vector construction. A forged HMAC identifier also caused a 32-byte write past a zero-length AUTH chunk, providing a primitive for a local privilege escalation chain. Validate the cookie's RANDOM, HMACS, and CHUNKS parameters at the cookie trust boundary before copying them into the association. Reject invalid types, malformed lengths, unsupported HMAC identifiers, HMAC lists without SHA1, and forbidden chunk ids.

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Meta Information

Published
2026-08-26
Last Modified
2026-08-26
Generated
2026-08-26
AI Q&A
2026-08-26
EPSS Evaluated
N/A
NVD
CVE-2026-74752
EUVD
EUVD-2026-66582

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 improper validation of cookie authentication state during SCTP (Stream Control Transmission Protocol) communication. When cookie authentication is disabled, an attacker can forge malicious cookie data to manipulate AUTH fields, leading to potential out-of-bounds reads or memory corruption. This occurs because the system fails to validate the RANDOM length, HMAC list, or CHUNKS list against local arrays before processing.

Detection Guidance

This vulnerability affects the Linux kernel's SCTP implementation. Detection requires checking kernel version and SCTP configuration. Use 'uname -r' to check kernel version and 'sysctl net.sctp' to review SCTP settings. Monitor for unusual network traffic patterns or crashes in SCTP-related processes.

Impact Analysis

This vulnerability could allow an attacker to execute arbitrary code or escalate privileges on a vulnerable system. By crafting malicious cookie data, an attacker might trigger memory corruption, leading to crashes or unauthorized access. Systems using SCTP with cookie authentication disabled are particularly at risk.

Mitigation Strategies

Apply the latest kernel security patches immediately. Disable SCTP if not required using 'sysctl -w net.sctp.disabled=1'. Restrict network access to SCTP ports (typically 9999/udp) via firewall rules. Monitor system logs for SCTP-related errors or crashes.

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