VulnerabilityDeferred

CVE-2025-21620

When you send a request with the Authorization header to one domain, and the response asks to redirect to a different domain, Deno'sfetch() redirect handling creates a follow-up redirect request that keeps the original Authorization header, leaking its…

HIGH 7.5EPSS 0.51%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. When you send a request with the Authorization header to one domain, and the response asks to redirect to a different domain, Deno'sfetch() redirect handling creates a follow-up redirect request that keeps the original Authorization header, leaking its content to that second domain. This vulnerability is fixed in 2.1.2.

CVSS 3.1: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.51% probability · 42th percentile
CISA KEV: Not listed
Weakness: CWE-200
Source: security-advisories@github.com

References

https://github.com/denoland/deno/security/advisories/GHSA-f27p-cmv8-xhm6

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.