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

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-04 · updated 2026-09-23
Weakness: CWE-601

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.

References

https://github.com/dubinc/dub
https://github.com/dubinc/dub/blob/73415cf5e6be13ce9adb7ba5e97474307db34a17/apps/web/lib/middleware/utils/get-final-url.ts
https://github.com/dubinc/dub/issues/4337
https://www.vulncheck.com/advisories/dub-open-redirect-via-unrestricted-redir-url-parameter

Get alerted when CVE-2026-85676 or the next vulnerability affects your stack