CVE-2021-23997

Firefox ESR and 1 other: Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the…

CVE-2021-23997 is fixed in 4 products on 2 platforms, first by firefox 88.0+build2-0ubuntu0.18.04.2, released April 25, 2021. It is not reported as exploited. Patch Radar priority: High.

HighFixed on 2 platforms
CVSS
8.8
Medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0082
57th percentile

Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the font cache. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

Where it's fixed

ProductFixed inFixReleased
Windows apps
Mozilla Firefox ESR (en-US) 91.0 Mozilla Firefox ESR (en-US) 91.0 Aug 4, 2021
Linux
firefox · Ubuntu 18.04.6 LTS (bionic) 88.0+build2-0ubuntu0.18.04.2 firefox 88.0+build2-0ubuntu0.18.04.2 Apr 25, 2021
firefox · Ubuntu 20.04 LTS (focal) 88.0+build2-0ubuntu0.20.04.1 firefox 88.0+build2-0ubuntu0.20.04.1 Apr 25, 2021
firefox-geckodriver · Ubuntu 18.04.6 LTS (bionic) 88.0+build2-0ubuntu0.18.04.2 firefox-geckodriver 88.0+build2-0ubuntu0.18.04.2 Apr 25, 2021
firefox-geckodriver · Ubuntu 20.04 LTS (focal) 88.0+build2-0ubuntu0.20.04.1 firefox-geckodriver 88.0+build2-0ubuntu0.20.04.1 Apr 25, 2021
firefox-mozsymbols · Ubuntu 18.04.6 LTS (bionic) 88.0+build2-0ubuntu0.18.04.2 firefox-mozsymbols 88.0+build2-0ubuntu0.18.04.2 Apr 25, 2021
firefox-mozsymbols · Ubuntu 20.04 LTS (focal) 88.0+build2-0ubuntu0.20.04.1 firefox-mozsymbols 88.0+build2-0ubuntu0.20.04.1 Apr 25, 2021

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