CVE-2026-89476 (CVSS 7.5)

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix stream->outcnt underflow on duplicate RECONF responses A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it. Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0069

Probability of exploitation

0.51%

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/041f7df5a929d3e7435dd8387e8ea17f2d412b7d https://git.kernel.org/stable/c/092acd3c55a4077b00489064615d8d2d898daf91 https://git.kernel.org/stable/c/2d867663c563e8009257b9edf9c8ec75d9bbf19a https://git.kernel.org/stable/c/3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e https://git.kernel.org/stable/c/59f61c39cb99ee1737bd742a20094fe5653389bb https://git.kernel.org/stable/c/793519e343867ee9a3e84f6cac07f81f2aec7b5d https://git.kernel.org/stable/c/8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68 https://git.kernel.org/stable/c/d02a5794c3deedcb8476d017fcee2b7aaedab2e1

Frequently Asked Questions

What is CVE-2026-89476? +

In the Linux kernel, the following vulnerability has been resolved: sctp: fix stream->outcnt underflow on duplicate RECONF responses A cached RECONF chunk may contain more than one request parameter. A duplicate response can therefore find and process the same ADD_OUT request again while another parameter is still outstanding, rolling back outcnt twice and possibly underflowing it. Track outstanding request types as bits and clear each bit after its first response. Later responses for the same request are then ignored. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-89476? +

CVE-2026-89476 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0069, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-89476? +

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-2026-89476