CVE-2025-1009: An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 135 : patch affected systems as a priority.
Data as of 30 Oct 2026, 01:09 UTC
- Patch
- Available – fixed in 135, 128.7, 115.20
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation 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 115.20 and 128.7, and Thunderbird 135 and 128.7. Users and administrators should update to these versions or later to remediate the vulnerability. No additional mitigation steps are required beyond applying these official patches.
Description
A use-after-free vulnerability exists in Firefox and Thunderbird due to crafted XSLT data, which can lead to a potentially exploitable crash. This issue affects Firefox versions prior to 135, Firefox ESR versions prior to 115.20 and 128.7, and Thunderbird versions prior to 128.7 and 135. The vulnerability was reported by Ivan Fratric of Google Project Zero and is classified as critical with a CVSS score of 9.8. Mozilla has released fixes for this vulnerability in Firefox 135, Firefox ESR 115.20 and 128.7, and Thunderbird 135 and 128.7.
References
- nvd.nist.gov/vuln/detail/CVE-2025-1009 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1936613 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/02/msg00005.html (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/mfsa2025-08 (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)