CVE-2025-21620 | Deno's authorization headers not dropped when redirecting cross-origin

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.

Published: 2025-01-06 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-21620 is rated Moderate Risk (43.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.50%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-21620

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.26% 0.50% +0.23%
2 2026-05-28 0.19% 0.26% +0.07%
3 2026-03-17 — 0.19% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21620

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-21620

GitHub Security Advisory for CVE-2025-21620

GHSA-f27p-cmv8-xhm6 · Severity: high · Ecosystem: rust — fetch: Authorization headers not dropped when redirecting cross-origin

OS Trackers for CVE-2025-21620

vendor priority summary link
alpine high CVE-2025-21620: 1 source package rows (deno); 3 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 3. https://security.alpinelinux.org/vuln/CVE-2025-21620

Affected software / configurations for CVE-2025-21620

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-21620

cvelogic Threat Intelligence