CVE-2021-21354

Name: CVE-2021-21354
Creator: NVD / NIST
Published: 2021-03-08T19:15:13.333+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 1.36%

Last modified Jun 17, 2026

CVE-2021-21354 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Pollbot is open source software which "frees its human masters from the toilsome task of polling for the state of things during the Firefox release process." In Pollbot before version 1.4.4 there is an open redirection vulnerability in the path of "https://pollbot.services.mozilla.com/". An attacker can redirect anyone to malicious sites. EPSS estimates a 1.36% chance of exploitation in the next 30 days.

Description

Pollbot is open source software which "frees its human masters from the toilsome task of polling for the state of things during the Firefox release process." In Pollbot before version 1.4.4 there is an open redirection vulnerability in the path of "https://pollbot.services.mozilla.com/". An attacker can redirect anyone to malicious sites. To Reproduce type in this URL: "https://pollbot.services.mozilla.com//evil.com/". Affected versions will redirect to that website when you inject a payload like "//evil.com/". This is fixed in version 1.4.4.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

1.36%

68.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-601

Affected Software

Vendor	Product	Versions
Mozilla	Pollbot	< 1.4.4

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1694684Issue Tracking, Permissions Required, Third Party Advisory
https://cheatsheetseries.owasp.org/cheatsheets/Unvalidated_Redirects_and_Forwards_Cheat_Sheet.htmlThird Party Advisory
https://github.com/mozilla/PollBot/commit/6db74a4fcbff258c7cdf51a6ff0724fc10c485e5Patch, Third Party Advisory
https://github.com/mozilla/PollBot/pull/333Patch, Third Party Advisory
https://github.com/mozilla/PollBot/releases/tag/v1.4.4Third Party Advisory
https://github.com/mozilla/PollBot/security/advisories/GHSA-jhgx-wmq8-jc24Exploit, Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1694684Issue Tracking, Permissions Required, Third Party Advisory
https://cheatsheetseries.owasp.org/cheatsheets/Unvalidated_Redirects_and_Forwards_Cheat_Sheet.htmlThird Party Advisory
https://github.com/mozilla/PollBot/commit/6db74a4fcbff258c7cdf51a6ff0724fc10c485e5Patch, Third Party Advisory
https://github.com/mozilla/PollBot/pull/333Patch, Third Party Advisory
https://github.com/mozilla/PollBot/releases/tag/v1.4.4Third Party Advisory
https://github.com/mozilla/PollBot/security/advisories/GHSA-jhgx-wmq8-jc24Exploit, Third Party Advisory

Timeline

Published: Mar 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21354?

How severe is CVE-2021-21354?

CVE-2021-21354 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 1.36% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21354?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21354?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST