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Public proof of conceptFix available

CVE-2025-62727

A public proof of concept exists; no exploitation attested.

  • Published2025-10-28
  • Fixed in0.49.1
  • WeaknessCWE-407

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2025-10-2821:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2025-62727?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2025-62727?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV
starlette
BranchAffectedFixed in
0.x≥ 0.39.0, < 0.49.10.49.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • RHSA-2026:22993 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: satellite/foreman-mcp-server-rhel9 container image available as a Technology Preview

  • RHSA-2026:3462 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (ROCm)

  • RHSA-2026:3461 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (CUDA)

  • RHSA-2025:23080 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat AI Inference Server Model Optimization Tools 3.2.2 (CUDA)

  • RHSA-2025:23079 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (ROCm)

  • RHSA-2025:23078 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (CUDA)

1 more advisory

Full record on NVD

Fix

  1. Update starlette to 0.49.1
  2. Vendor fix Red Hat Product Security RHSA-2026:22993 · 1 productFor Satellite MCP integration see the Red Hat Satellite documentation.
  3. Vendor fix Red Hat Product Security RHSA-2026:3462 · 1 productFor more information visit https://access.redhat.com/errata/RHSA-2026:3462
  4. Vendor fix Red Hat Product Security RHSA-2026:3461 · 2 productsFor more information visit https://access.redhat.com/errata/RHSA-2026:3461
  5. Vendor fix Red Hat Product Security RHSA-2025:23080 · 2 productsFor more information visit https://access.redhat.com/errata/RHSA-2025:23080
  6. Vendor fix Red Hat Product Security RHSA-2025:23079 · 1 productFor more information visit https://access.redhat.com/errata/RHSA-2025:23079
  7. Vendor fix Red Hat Product Security RHSA-2025:23078 · 2 productsFor more information visit https://access.redhat.com/errata/RHSA-2025:23078

Detection

read 2026-10-23 19:24 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedch4n3-yoon/CVE-2025-62727-Demo
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2025-10-28
  • OpenCVESSVC decisionpoc—
  • CNACVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-407read 2026-10-23
  • FIRST EPSSEPSS score0.8 %2026-10-23
  • PoC-in-GitHubproof of concept1read 2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2025-10-28
Last Modified
2026-10-08
NVD status
Deferred

Frequently asked questions

What is CVE-2025-62727?

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.

Is CVE-2025-62727 actively exploited?

A proof-of-concept exploit exists for CVE-2025-62727, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2025-62727?

CVE-2025-62727 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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