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Fencer Vulns
medium 4.3

CVE-2021-29962 json

Firefox for Android would become unstable and hard-to-recover when a website opened too many popups.

published 2021-06-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-16421

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

Firefox for Android would become unstable and hard-to-recover when a website opened too many popups. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 89.

Patch / fix

  • Mozilla Firefox 89
  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1

  • firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +8 more 89.0-r0
  • librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 89.0-r0

alpine advisories ALPINE-CVE-2021-29962

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • Mozilla Firefox

Classification

Weakness
  • CWE-404 Improper Resource Shutdown or Release

References

Sources

Fencer Vulns 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.