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Fencer Intel
high 7.4

CVE-2021-21354 json

Open redirect in pollbot

published 5y ago modified 4mo ago also EUVD-2021-8677

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

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.

Patch / fix

  • mozilla pollbot 1.4.4

Is CVE-2021-21354 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.37% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/mozilla/PollBot/security/advisories/GHSA-jhgx-wmq8-jc24 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Affected products

  • mozilla PollBot

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.