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Fencer Vulns
high 8.8

CVE-2021-29990 json

Mozilla developers and community members reported memory safety bugs present in Firefox 90.

published 2021-08-17 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-16449

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

Mozilla developers and community members reported memory safety bugs present in Firefox 90. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 91.

Patch / fix

  • Mozilla Firefox 91
  • firefox Ubuntu 18.04 LTS 91.0+build2-0ubuntu0.18.04.1
  • firefox Ubuntu 20.04 LTS 91.0+build2-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2021-29990

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 91.9.0-112.104.1
  • MozillaFirefox SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 91.9.0-150000.150.34.1
  • MozillaFirefox SLE Module for Desktop Applications 15 SP3, SLE Module for Desktop Applications 15 SP2 91.2.0-8.54.1
  • MozillaFirefox-branding-SLE SLE Module for Desktop Applications 15 SP3, SLE Module for Desktop Applications 15 SP2 91-9.5.1
  • MozillaFirefox SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 91.2.0-3.155.2
  • MozillaFirefox-branding-SLE SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 91-4.19.1
  • MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 91.1.0-112.71.1
  • MozillaFirefox-branding-SLE SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +10 more 91-35.6.6

suse advisories SUSE-SU-2022:1582-1SUSE-SU-2022:1577-1SUSE-SU-2021:14826-1SUSE-SU-2021:3451-1SUSE-SU-2021:3331-1SUSE-SU-2021:14821-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2
  • MozillaFirefox openSUSE Leap 15.2 91.2.0-lp152.2.67.1
  • rust-cbindgen openSUSE Leap 15.2 0.19.0-lp152.2.7.1
  • MozillaFirefox openSUSE Leap 15.3 91.2.0-8.54.1
  • MozillaFirefox-branding-SLE openSUSE Leap 15.3 91-9.5.1
  • rust-cbindgen openSUSE Leap 15.3 0.19.0-1.9.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2021:1367-1openSUSE-SU-2021:3451-1openSUSE-SU-2021:3331-1

  • firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +6 more 92.0.1-r0
  • librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 92.0.1-r0

alpine advisories ALPINE-CVE-2021-29990

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

  • firefox Arch Linux 91.0-1

arch linux advisories AVG-2269

Exploit prediction

1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Firefox

Classification

Weakness

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.