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CVE Record

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

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().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-46089 is a Linux kernel zram bug where certain partial discard requests may never complete. The documented impact is an operation hanging indefinitely, not data theft or code execution. Severity is not published in the provided sources, so urgency depends on whether the environment uses zram and discard operations.

Executive priority

Treat this as a targeted availability concern rather than a confirmed breach risk. Prioritize routine kernel patching for systems that use zram, especially operational platforms where stuck maintenance jobs could affect reliability.

Technical view

The zram driver returns early for unsupported partial discard requests but failed to call bio_endio. As a result, callers such as blkdiscard can sleep indefinitely in submit_bio_wait. Kernel stable commits are referenced as fixes, but the provided version data is incomplete and inconsistent.

Likely exposure

Exposure is most likely on Linux systems using zram block devices where discard operations can be issued. The source example involves a 64 KB page size and 4 KB partial discard. Systems not using zram are unlikely to be affected by this specific path.

Exploitation context

The bundle does not cite active exploitation, KEV listing, remote attackability, privilege requirements, or weaponized exploit evidence. The described trigger is a local discard operation against a zram device that causes the caller to wait indefinitely.

Researcher notes

The key defect is missing completion handling on an unsupported partial discard path. Evidence supports an indefinite wait condition. The bundle lacks CVSS, CWE, precise privilege model, and clean affected-version ranges, so avoid overstating reach or impact.

Mitigation direction

  • Check vendor kernel advisories for CVE-2026-46089 applicability and fixed packages.
  • Prioritize updates on systems that use zram with discard-capable workflows.
  • Apply kernel updates containing one of the referenced stable fixes.
  • Where patching is delayed, review operational reliance on zram discard behavior.

Validation and detection

  • Inventory Linux hosts using zram devices.
  • Compare running kernel builds against vendor guidance for CVE-2026-46089.
  • Confirm whether kernel packages include the referenced zram endio fix.
  • Review monitoring for stuck discard or storage maintenance jobs involving zram.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-46089 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux0120dd6e4e202e19a0e011e486fb2da40a5ea279, 0120dd6e4e202e19a0e011e486fb2da40a5ea279, 0120dd6e4e202e19a0e011e486fb2da40a5ea279, 0120dd6e4e202e19a0e011e486fb2da40a5ea279, 0120dd6e4e202e19a0e011e486fb2da40a5ea279unaffected
LinuxLinux6.4, 0, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1affected
Weakness

CWE details

No CWE listed

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