How severe is CVE-2025-4366?

No CVSS score has been assigned to CVE-2025-4366 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-4366?

CVE-2025-4366 affects the following packages: pingora-core (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2025-4366?

Update pingora-core to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-4366 is resolved across your whole dependency graph.

How do I detect CVE-2025-4366 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pingora-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-4366 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2025-4366 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-4366 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-4366?

CVE-2025-4366 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-4366?

CVE-2025-4366 is classified as CWE-444 (CWE-444). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-4366 published, and has it been updated?

CVE-2025-4366 was published on May 22, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

Not in CISA KEV

CVE-2025-4366 — pingora-core

Fix: cloudflare/pingora@fda3317

CVE-2025-4366 is a CWE-444 vulnerability in pingora-core. A fix is available for pingora-core — see the affected versions and patch details below.

Request Smuggling Vulnerability in Pingora

Also known asGHSA-93c7-7xqw-w357RUSTSEC-2025-0037

Published

May 22, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-4366.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🦀pingora-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Fixed in: https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact: The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`pingora-core`	all versions	0.5.0`cargo update -p pingora-core --precise 0.5.0`

Affected Products

1 product · 1 configurations

Application

pingoracloudflare

< 0.5.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pingora-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pingora-core to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-4366 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning. ### Fixed in https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff ### Impact The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 co

O3 Security · Impact-Aware SCA

Is CVE-2025-4366 in your dependencies?

Find it across crates.io, including transitive dependencies.

Scan my dependencies How O3 SCA works