Medium [CVE-2026-68385] Linux kernel (s390/checksum): Incorrect checksum calculation in csum_partial
This medium-severity Red Hat Linux advisory covers CVE-2026-68385 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux for NVIDIA 26, Red Hat package: kernel.
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Summary
In the Linux kernel, the following vulnerability has been resolved: s390/checksum: Fix csum_partial() without vector facility Currently csum_partial() calls csum_copy() with copy=false and dst=NULL.
On machines without the vector facility, csum_copy() falls back to cksm(dst,...), causing the checksum to be calculated from address zero instead of the source buffer. The VX implementation already checksums data loaded from src.
Make the fallback do the same by passing src to cksm(). A flaw was found in the Linux kernel's s390 architecture checksumming mechanism.
On systems without a vector facility, the csum_partial() function incorrectly calculates checksums. This occurs because the csum_copy() function, when called with specific parameters, falls back to calculating the checksum from memory address zero instead of the intended source buffer.
This can lead to incorrect checksums, potentially affecting data integrity within the kernel. Red Hat severity: Moderate — CVSS 4.4 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L).
Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux for NVIDIA 26.
Red Hat lists Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4 as not affected. Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
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