CVE-2026-46089: zram: do not forget to endio for partial discard requests

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-25

Description

In the Linux kernel, the following vulnerability has been resolved: zram: do not forget to endio for partial discard requests As reported by Qu Wenruo and Avinesh Kumar, the following getconf PAGESIZE 65536 blkdiscard -p 4k /dev/zram0 takes literally forever to complete. zram doesn't support partial discards and just returns immediately w/o doing any discard work in such cases. The problem is that we forget to endio on our way out, so blkdiscard sleeps forever in submit_bio_wait(). Fix this by jumping to end_bio label, which does bio_endio().

Affected products

Linux kernel: from 6.4 before 6.6.140; from 6.7 before 6.12.86; from 6.13 before 6.18.27; from 6.19 before 7.0.4 — fixed in 6.12.86, 6.18.27, 6.6.140, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.86, 6.18.27, 6.6.140, 7.0.4. Check the vendor advisory for mitigations.

References

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