CVE-2026-99124

Description

In the Linux kernel, the following vulnerability has been resolved: s390/pci: Fix leak of uninitialized kernel data in SCLP report While report_error_write() checks that the provided buffer is at least as large as the header struct, but not that it is large enough to contain the report with the length claimed by report->length. If user-space provides a short buffer, meaning a larger report->length than the actually written payload, up to around 4K of kernel data from past the kmalloc(len + 1) sized buffer allocated in kernfs_fop_write_iter() will leak into the SCLP report. However, as the entity processing the SCLP is privileged and able to access at least the page including the report, this does not leak data that entity could not access but it is still an out of bounds read and a malformed error report that should be rejected.

Is your site exposed to CVE-2026-99124?

Run a free security scan — no signup, results in seconds.

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.07%

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/126a7c227d8543e13903dd5622640c1f0fcc5a16 https://git.kernel.org/stable/c/332f2d867f64dd530517e9a58394e3eab454df12 https://git.kernel.org/stable/c/61ce6f9a527932f4482ebe00847490f17d63a0d1 https://git.kernel.org/stable/c/8ac60ae2a307a50b599bf5d300b448d638f3ba29 https://git.kernel.org/stable/c/ad1be38823d4b6dbc88648da296ca0c0f8824a55 https://git.kernel.org/stable/c/ba5001db9bb23ff7d2ea328c405c287ffb07786f https://git.kernel.org/stable/c/eb10f25e32576bb3dbbea4457648614537f04211 https://git.kernel.org/stable/c/ff31c34e921d11c7da3d7664ce495106267ca408

Frequently Asked Questions

What is CVE-2026-99124? +

In the Linux kernel, the following vulnerability has been resolved: s390/pci: Fix leak of uninitialized kernel data in SCLP report While report_error_write() checks that the provided buffer is at least as large as the header struct, but not that it is large enough to contain the report with the length claimed by report->length. If user-space provides a short buffer, meaning a larger report->length than the actually written payload, up to around 4K of kernel data from past the kmalloc(len + 1) sized buffer allocated in kernfs_fop_write_iter() will leak into the SCLP report. However, as the entity processing the SCLP is privileged and able to access at least the page including the report, this does not leak data that entity could not access but it is still an out of bounds read and a malformed error report that should be rejected.

How do I check if I'm vulnerable to CVE-2026-99124? +

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.