CVE-2026-117921: Mozilla Firefox · Use-after-free in the CSS Parsing and Computation component

Disclosed

The CVE record is public on cve.org. Its publication is t = 0.

Detectable

A public nuclei template can find exposed instances, for defenders and attackers alike.

Weaponised

Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.

Exploited in the wild

CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.

Observed by OffSeq Mirage

OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.