Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability
Mozilla · Firefox, Firefox ESR, and Thunderbird
The flaw is a use-after-free vulnerability in the SVG Animation component of Mozilla Firefox, Firefox ESR, and Thunderbird. An attacker can exploit it over the network without authentication or user interaction, with low attack complexity, to compromise confidentiality.
A use-after-free vulnerability in SVG Animation has been discovered. An exploit built on this vulnerability has been discovered in the wild targeting Firefox and Tor Browser users on Windows. This vulnerability affects Firefox < 50.0.2, Firefox ESR < 45.5.1, and Thunderbird < 45.5.1.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 18 months before it was disclosed. Public exploit code (Metasploit) was available 18 months before disclosure.
- First seen exploitedVulnCheck KEV evidence18 mo before
- Public exploit codeMetasploit18 mo before
- Disclosedday 0
- Added to CISA KEVEU database agrees+5 yrs
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo high- or medium-confidence techniques. The 2 available links are lower confidence and listed below.
Lower-confidence links (2)
These come from early or generic mappings, text matching, or contradict this CVE’s details (for example a public-facing technique on a bug that needs a user to open a file). Shown for completeness.
- Drive-by CompromiseT1189 server-side bug exploitable without user interaction; client-execution technique does not fit
- Exploitation for Client ExecutionT1203 server-side bug exploitable without user interaction; client-execution technique does not fit
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX