CVE-2025-62727
unknown
CVSS v3
—
CVSS v2
—
VIR risk
—
Description
Starlette is a lightweight ASGI framework/toolkit. Starting in version 0.39.0 and prior to version 0.49.1 , an unauthenticated attacker can send a crafted HTTP Range header that triggers quadratic-time processing in Starlette's FileResponse Range parsing/merging logic. This enables CPU exhaustion per request, causing denial‑of‑service for endpoints serving files (e.g., StaticFiles or any use of FileResponse). This vulnerability is fixed in 0.49.1.
Predictions
Exploit likelihood
30%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2025-62727
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2025-62727.html
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 0 |
| debian | bullseye | fixed | 0 |
| debian | forky | fixed | 0.50.0-1 |
| debian | sid | fixed | 0.50.0-1 |
| debian | trixie | fixed | 0.46.1-3+deb13u1 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| PyPI | starlette | >=0.39.0,<0.49.1 | 0.49.1 |
References
- https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
- https://nvd.nist.gov/vuln/detail/CVE-2025-62727
- https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5
- https://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c
- https://github.com/Kludex/starlette
- https://github.com/Kludex/starlette/releases/tag/0.49.1
- https://www.suse.com/security/cve/CVE-2025-62727.html
- https://security-tracker.debian.org/tracker/CVE-2025-62727
Verify integrity in audit chain (admin only). AS-IS.