CVE-2026-98323 (CVSS 9.8)

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Bound fragmented header copies by the remaining length siw_get_hdr() can receive an extended DDP/RDMAP header across more than one TCP callback. The first callback may receive most of the header, while the next one still limits the copy to hdrlen - MIN_DDP_HDR instead of the number of missing bytes. This makes the destination move past the end of the header and overwrite the receive state, including fpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd value as a copy offset, which creates an OOB write. Use the number of header bytes already received when calculating the next copy length.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0051

Probability of exploitation

0.44%

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/262dcd809723723ed8a4e05437ec7e9c21a8f17e https://git.kernel.org/stable/c/2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7 https://git.kernel.org/stable/c/8628f8ebf41669302513fb3f0bf0eba38b226742 https://git.kernel.org/stable/c/9ff797e516dbc1ecb73701ec4c24055712d44411 https://git.kernel.org/stable/c/af9f5b474a260ad23ffb9793d716a5e3bbce3b48 https://git.kernel.org/stable/c/b72dcfb9bf1f0f0147cda03dc59e4002a315067f https://git.kernel.org/stable/c/e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d https://git.kernel.org/stable/c/eb4d7a946970469b3ab0c762432bf161d5b0836c

Frequently Asked Questions

What is CVE-2026-98323? +

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Bound fragmented header copies by the remaining length siw_get_hdr() can receive an extended DDP/RDMAP header across more than one TCP callback. The first callback may receive most of the header, while the next one still limits the copy to hdrlen - MIN_DDP_HDR instead of the number of missing bytes. This makes the destination move past the end of the header and overwrite the receive state, including fpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd value as a copy offset, which creates an OOB write. Use the number of header bytes already received when calculating the next copy length. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-98323? +

CVE-2026-98323 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0051, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-98323? +

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-2026-98323