Vulnerability · Published Sep 4, 2026 · Assigned by VulnCheck

CVE-2026-85676Dub Open Redirect via Unrestricted redir_url Parameter

Medium 4.3

In plain English

A medium-severity open redirect in dub from dubinc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.4%top 63.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Dub contains an open redirect vulnerability in the redir_url query parameter that is accepted on every short link without validation or domain allowlist enforcement. Attackers can append the redir_url parameter to any short link to redirect visitors to arbitrary external URLs through the trusted Dub domain, bypassing destination blacklists and potentially enabling phishing attacks with link cloaking enabled.

Affected products (as reported)

Vendor	Product	Versions
dubinc	dub	0 – through 73415cf5e6be13ce9adb7ba5e97474307db34a17

Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

References

GitHub Issue #4337 issue-tracking
https://github.com/dubinc/dub product
https://github.com/dubinc/dub/blob/73415cf5e6be13ce9adb7ba5e97474307db34a17/apps/web/lib/middleware/utils/get-final-url.ts technical-description
VulnCheck Advisory: Dub Open Redirect via Unrestricted redir_url Parameter third-party-advisory