CVE-2021-23977
Firefox for Android suffered from a time-of-check-time-of-use vulnerability that allowed a malicious application to read sensitive data from application directories.
Does this matter?
Lower severity and a low EPSS score (0.88%). Track it; it rarely justifies an emergency change on its own.
Description
Firefox for Android suffered from a time-of-check-time-of-use vulnerability that allowed a malicious application to read sensitive data from application directories. Note: This issue is only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 86.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
- EPSS
- 0.88% probability · 59th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-367
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 0.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1684761Issue Tracking, Permissions Required, Vendor Advisory
- https://security.gentoo.org/glsa/202104-10Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-07/Release Notes, Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1684761Issue Tracking, Permissions Required, Vendor Advisory
- https://security.gentoo.org/glsa/202104-10Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-07/Release Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.