CVE-2026-85676: Open Redirect (CVSS 4.3)

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.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-601 CWE-601

References

Other 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

Frequently Asked Questions

What is CVE-2026-85676? +

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. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-85676? +

CVE-2026-85676 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-85676? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-85676