CVE-2026-44903

Prometheus is an open-source monitoring system and time series database. From 2.49.0 to before 3.5.3 and 3.11.3, in the Prometheus server's legacy web UI enabled via the command-line flag --enable-feature=old-ui, the histogram heatmap chart view does not escape le label values when inserting them...

CVE-2026-44903

CVE-2026-44903 affects Prometheus servers with the legacy web UI enabled. From 2.49.0 up to before 3.5.3 and 3.11.3, histogram heatmap axis tick labels aren’t escaped when inserting metric label values into HTML, allowing an attacker who can inject crafted metrics to run JavaScript in the browser...

CVE-2026-44903: Improper Neutralization of Input During Web Page Generation

Prometheus is an open-source monitoring system and time series database. From 2.49.0 to before 3.5.3 and 3.11.3, in the Prometheus server's legacy web UI enabled via the command-line flag --enable-feature=old-ui, the histogram heatmap chart view does not escape le label values when inserting them...

Prometheus vulnerable to stored XSS via crafted histogram bucket label values in the old web UI heatmap display

Impact In the Prometheus server's legacy web UI enabled via the command-line flag --enable-feature=old-ui, the histogram heatmap chart view does not escape le label values when inserting them into the HTML for use as axis tick mark labels. An attacker who can inject crafted metrics e.g. via a...