CVE-2026-46089 Linux CVE debrief

Who should care

System administrators running Linux systems with zram enabled for swap or compressed block storage; kernel maintainers and distribution packagers; developers of storage management tools that issue discard operations.

Technical summary

The zram compressed RAM block device driver in the Linux kernel contains a bug where partial discard requests are not properly completed. When a discard operation with a partial block size (e.g., 4KB on a system with 64KB pages) is submitted to /dev/zram0, the driver recognizes it cannot process the partial discard and returns early. However, it fails to call bio_endio() to signal completion, causing the submitting process to sleep indefinitely in submit_bio_wait(). The fix redirects the early return path to the end_bio label to ensure proper I/O completion.

Defensive priority

medium

Recommended defensive actions

• Apply kernel updates containing the referenced stable branch commits when available from your Linux distribution
• Monitor NVD for CVSS scoring once analysis is complete
• Review systems using zram for swap or compressed block storage
• Test blkdiscard operations on zram devices after patching to verify resolution

Evidence notes

CVE published 2026-05-27. Linux kernel stable branch commits provided as references. No CVSS score assigned; NVD status is Awaiting Analysis. Not listed in CISA KEV.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.