CVE-2021-4138
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.8%
exploitation probability
0.8%top 43% of all CVEs
observed exploitation
nono source reports it
Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.
Affected products
Mozilla · geckodriver