CVE-2026-44903 - Prometheus: Stored XSS via crafted histogram bucket label values in the heatmap display of the old Prometheus web UI
CVE ID :CVE-2026-44903
Published : May 26, 2026, 10:16 p.m. | 44 minutes ago
Description :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 into the HTML for use as axis tick mark labels. An attacker who can inject crafted metrics can execute JavaScript in the browser of any Prometheus user who views the metric in the heatmap chart UI. This vulnerability is fixed in 3.5.3 and 3.11.3.
Severity: 5.1 | MEDIUM
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Published : May 26, 2026, 10:16 p.m. | 44 minutes ago
Description :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 into the HTML for use as axis tick mark labels. An attacker who can inject crafted metrics can execute JavaScript in the browser of any Prometheus user who views the metric in the heatmap chart UI. This vulnerability is fixed in 3.5.3 and 3.11.3.
Severity: 5.1 | MEDIUM
Visit the link for more details, such as CVSS details, affected products, timeline, and more...