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Vulnerabilities

Vulnerability · CVE-2025-62727

Starlette is a lightweight ASGI framework/toolkit.

Published Oct 28, 2025 · catalog updated Nov 4, 2025 · Kludex

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2025-62727 is not in CISA KEV. FIRST estimates a 80.00% chance of exploitation in the next 30 days. Check whether you run Kludex.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
80.00%
Remediation
Version ranges on file
Affected products
vendor Kludex starlette 0.39.0, < 0.49.1

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Kludex starlette 0.39.0, < 0.49.10.39.0, < 0.49.1

How to fix CVE-2025-62727

  • Upgrade

    CVE-2025-62727 lists a fix boundary at 0.49.1. Compare the installed build with that boundary before you change production.

  • Version check

    Affected < 0.49.1

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-62727 is not in CISA KEV. FIRST estimates a 80.00% chance of exploitation in the next 30 days. Check whether you run Kludex.

Which versions are affected?

Compare what you have installed with Kludex starlette 0.39.0, < 0.49.1 0.39.0, < 0.49.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 80.00%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 28, 2025 · EUVD

    Detected

    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 Fi

  2. Nov 4, 2025 · EUVD

    Updated

    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 Fi

Sources

  • EUVDVulnerability recordEUVD-2025-36555

    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 enabl

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 4, 2025. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • EUVDOct 25, 2026