CVE-2025-1013: A race condition could have led to private browsing tabs being opened in normal browsing windows
Source GCVE Database
Not known to be exploited · CVSS 6.5 Medium · fixed in 135 : update affected systems when convenient.
Data as of 30 Oct 2026, 01:10 UTC
- Patch
- Available – fixed in 135, 128.7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 4 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 135, Firefox ESR 128.7, Thunderbird 135, and Thunderbird 128.7. Users and administrators should update affected products to these versions or later to remediate the issue. No additional mitigation steps are required once the software is updated.
Description
A race condition vulnerability in Firefox and Thunderbird could cause private browsing tabs to open in normal browsing windows, potentially leading to a privacy leak. This issue affects Firefox versions prior to 135, Firefox ESR versions prior to 128.7, and Thunderbird versions prior to 128.7 and 135. The vulnerability has a medium severity rating with a CVSS score of 6.5. Mozilla has fixed this issue in Firefox 135 and Thunderbird 135, as well as Firefox ESR 128.7 and Thunderbird 128.7.
References
- nvd.nist.gov/vuln/detail/CVE-2025-1013 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1932555 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/02/msg00006.html (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-07 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-09 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-10 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-11 (opens in a new tab)