CVE-2021-23975

Firefox ESR and 1 other: The developer page about:memory has a Measure function for exploring what object types the browser has…

CVE-2021-23975 is fixed in 4 products on 2 platforms, first by firefox 86.0+build3-0ubuntu0.18.04.1, released February 26, 2021. It is not reported as exploited. Patch Radar priority: Routine.

RoutineFixed on 2 platforms
CVSS
6.5
Low
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0101
63rd percentile

The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked we incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers. This vulnerability affects Firefox < 86.

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) 86.0+build3-0ubuntu0.18.04.1 firefox 86.0+build3-0ubuntu0.18.04.1 Feb 26, 2021
firefox · Ubuntu 20.04 LTS (focal) 86.0+build3-0ubuntu0.20.04.1 firefox 86.0+build3-0ubuntu0.20.04.1 Feb 26, 2021
firefox-geckodriver · Ubuntu 18.04.6 LTS (bionic) 86.0+build3-0ubuntu0.18.04.1 firefox-geckodriver 86.0+build3-0ubuntu0.18.04.1 Feb 26, 2021
firefox-geckodriver · Ubuntu 20.04 LTS (focal) 86.0+build3-0ubuntu0.20.04.1 firefox-geckodriver 86.0+build3-0ubuntu0.20.04.1 Feb 26, 2021
firefox-mozsymbols · Ubuntu 18.04.6 LTS (bionic) 86.0+build3-0ubuntu0.18.04.1 firefox-mozsymbols 86.0+build3-0ubuntu0.18.04.1 Feb 26, 2021
firefox-mozsymbols · Ubuntu 20.04 LTS (focal) 86.0+build3-0ubuntu0.20.04.1 firefox-mozsymbols 86.0+build3-0ubuntu0.20.04.1 Feb 26, 2021

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