CVE-2026-74704 (CVSS 8.2)

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter The sch_cake ACK filter parses packets to find the TCP header and filter duplicated ACKs if the flow is backlogged. The parsing code contains a WARN_ON(1) which can be triggered by a malformed IP header in certain cases. Depending on the system configuration, this leads either to either spamming dmesg with warnings, or a panic if panic_on_warn is set. The code already correctly skips the offending packet in the branch that triggers the warning, so the WARN_ON itself doesn't really serve any purpose. So just drop it altogether to avoid the inconvenient side effects.

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CVSS v3.1 Score

8.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

EPSS — Exploit Prediction

0.0044

Probability of exploitation

0.38%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/0c4882bff34558d8d53fb04c3e96da5c327c7dc8 https://git.kernel.org/stable/c/2504a76e5c0694e14e15562730e1339f2d9f9458 https://git.kernel.org/stable/c/2a33516f9ef59ad11844d4fc152f889449b5daf3 https://git.kernel.org/stable/c/a1ae353d8355407c1bea971d1c1af5e7f242bb7d https://git.kernel.org/stable/c/a4b52612004a5639c4bfc30ba93ba414b8326e2a https://git.kernel.org/stable/c/ae1b2f8e21a41e7c7e75511bea0c4ccc59ec1bd3 https://git.kernel.org/stable/c/c1693b7844a6c06d31a565e5a494948034dfd235 https://git.kernel.org/stable/c/cd2f1d9fe8a507c2dc86ad326fe221f121c47734

Frequently Asked Questions

What is CVE-2026-74704? +

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter The sch_cake ACK filter parses packets to find the TCP header and filter duplicated ACKs if the flow is backlogged. The parsing code contains a WARN_ON(1) which can be triggered by a malformed IP header in certain cases. Depending on the system configuration, this leads either to either spamming dmesg with warnings, or a panic if panic_on_warn is set. The code already correctly skips the offending packet in the branch that triggers the warning, so the WARN_ON itself doesn't really serve any purpose. So just drop it altogether to avoid the inconvenient side effects. It has a CVSS v3.1 base score of 8.2 (HIGH).

How severe is CVE-2026-74704? +

CVE-2026-74704 has a CVSS v3.1 score of 8.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0044, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-74704? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-74704