CVE-2025-62595 | Koa Vulnerable to Open Redirect via Trailing Double-Slash (//) in back Redirect Logic

Exp

Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality. In certain circumstances, an attacker can manipulate the Referer header to force a user’s browser to navigate to an external, potentially malicious website. This occurs because the implementation incorrectly treats some specially crafted URLs as safe relative paths. Exploiting this vulnerability could allow attackers to perform phishing, social engineering, or other redirect-based attacks on users of affected applications. This issue has been patched in version 3.0.3.

Published: 2025-10-21 Last update: 2026-01-20 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-62595 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.26%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2025-62595

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-62595

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 0.03% 0.26% +0.23%
2 2025-10-22 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-62595

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2025-62595

GitHub Security Advisory for CVE-2025-62595

GHSA-g8mr-fgfg-5qpc · Severity: medium · Ecosystem: npm — Koa Vulnerable to Open Redirect via Trailing Double-Slash (//) in back Redirect Logic

OS Trackers for CVE-2025-62595

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2025-62595
suse medium CVE-2025-62595 severity moderate: SUSE including 34 source package names (corepack20, corepack22, …), 165 product×package rows across 21 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS, … (21 product lines)): Known Not Affected 165. https://www.suse.com/security/cve/CVE-2025-62595/

Affected software / configurations for CVE-2025-62595

Vendor Product Version Raw CPE
koajs koa >= 3.0.1, < 3.0.3 cpe:2.3:a:koajs:koa:*:*:*:*:*:node.js:*:*
koajs koa 2.16.2 cpe:2.3:a:koajs:koa:2.16.2:*:*:*:*:node.js:*:*

References for CVE-2025-62595

cvelogic Threat Intelligence