A race condition could have led to private browsing tabs being opened in normal browsing windows. This could have resulted in a potential privacy leak. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
| Link | Tags |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1932555 | issue tracking |
| https://www.mozilla.org/security/advisories/mfsa2025-07/ | vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-09/ | vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-10/ | vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-11/ | vendor advisory |