CVE-2026-89456 (CVSS 7)

Description

In the Linux kernel, the following vulnerability has been resolved: s390/dasd: Propagate partial completion length across ERP recovery dasd_default_erp_postaction() copies the timing and device state from the finished ERP request back to the original request but drops proc_bytes. A request that was partially completed, an ESE read of a not-yet-allocated track returns fewer bytes than requested, and then recovered through the ERP chain loses its partial-completion length. __dasd_cleanup_cqr() then sees proc_bytes == 0 and completes the whole request instead of requeueing the remainder, silently returning zeroed data for the part that was never read. Carry proc_bytes over to the original request like the other per-request state.

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CVSS v3.1 Score

7.0

HIGH

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

EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.04%

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/15ec03452c18e8d288e519837d21b308300d74b2 https://git.kernel.org/stable/c/6b0954c8a259da1e4aa745989f82723947acfb46 https://git.kernel.org/stable/c/6fb5ba2e7e43173a3761e46f091070a8185efa14 https://git.kernel.org/stable/c/9e063165d3fe58db2a517717b830f17e82d03467 https://git.kernel.org/stable/c/ceafb262475ac6cb3a7d07b1102608be2b216b99 https://git.kernel.org/stable/c/d0a2f97d8c97134aa7f6a191940b7bab4bb42f5f https://git.kernel.org/stable/c/d6b8778b1b82aa3a8dbf8612080f635b834bd16b https://git.kernel.org/stable/c/f735b9710f0c8fe72c1060103e865f4ae678190b

Frequently Asked Questions

What is CVE-2026-89456? +

In the Linux kernel, the following vulnerability has been resolved: s390/dasd: Propagate partial completion length across ERP recovery dasd_default_erp_postaction() copies the timing and device state from the finished ERP request back to the original request but drops proc_bytes. A request that was partially completed, an ESE read of a not-yet-allocated track returns fewer bytes than requested, and then recovered through the ERP chain loses its partial-completion length. __dasd_cleanup_cqr() then sees proc_bytes == 0 and completes the whole request instead of requeueing the remainder, silently returning zeroed data for the part that was never read. Carry proc_bytes over to the original request like the other per-request state. It has a CVSS v3.1 base score of 7.0 (HIGH).

How severe is CVE-2026-89456? +

CVE-2026-89456 has a CVSS v3.1 score of 7.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0015, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-89456? +

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-2026-89456