# CVE-2026-44903: prometheus: Prometheus is an open-source monitoring system and time series database

CVE-2026-44903 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-44903, released May 26, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-44903
- Priority: Routine
- CVSS: 6.1 (medium)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 26, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | [OPENSUSE-SU-2026:21483-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21483-1.md) | Jul 30, 2026 |
| Linux | prometheus Debian 14 | 3.5.3+ds1-1 | [DEBIAN-CVE-2026-44903](https://patchblox.com/security/data/fix/linux/debian-cve-2026-44903.md) | May 26, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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