CVE-2026-44903
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
CVE-2026-44903 NameCVE-2026-44903 DescriptionPrometheus 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…
CVE-2026-44903
| Name | CVE-2026-44903 |
| 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1138261 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| prometheus (PTS) | bullseye | 2.24.1+ds-1 | fixed |
| bookworm | 2.42.0+ds-5 | fixed | |
| trixie | 2.53.3+ds1-2 | vulnerable | |
| forky, sid | 2.53.5+ds1-4 | vulnerable |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| prometheus | source | bullseye | (not affected) | |||
| prometheus | source | bookworm | (not affected) | |||
| prometheus | source | (unstable) | (unfixed) | 1138261 |
Notes
[bookworm] - prometheus <not-affected> (Vulnerable code introduced later)
[bullseye] - prometheus <not-affected> (Vulnerable code introduced later)
https://github.com/prometheus/prometheus/security/advisories/GHSA-fw8g-cg8f-9j28
Fixed by: https://github.com/prometheus/prometheus/commit/38f23b9075ced1de2b82d2dad8b2bebb1ecd5b7d
Introduced by: https://github.com/prometheus/prometheus/commit/2e205ee95c121d8d6da0d8984f0b3bc599acaa2a (v2.49.0-rc.0)
Apply commands
[bookworm] - prometheus <not-affected> (Vulnerable code introduced later)[bullseye] - prometheus <not-affected> (Vulnerable code introduced later)https://github.com/prometheus/prometheus/security/advisories/GHSA-fw8g-cg8f-9j28Fixed by: https://github.com/prometheus/prometheus/commit/38f23b9075ced1de2b82d2dad8b2bebb1ecd5b7dIntroduced by: https://github.com/prometheus/prometheus/commit/2e205ee95c121d8d6da0d8984f0b3bc599acaa2a (v2.49.0-rc.0)OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Affected | — |
| forky | Affected | — |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 0 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| Go | github.com/prometheus/prometheus | <0.311.3 | 0.311.3 |
| GO | github.com/prometheus/prometheus | < 0.311.3 | 0.311.3 |
References
- https://github.com/prometheus/prometheus/security/advisories/GHSA-fw8g-cg8f-9j28
- https://github.com/prometheus/prometheus/commit/38f23b9075ced1de2b82d2dad8b2bebb1ecd5b7d
- https://github.com/prometheus/prometheus
- https://www.suse.com/security/cve/CVE-2026-44903.html
- https://github.com/advisories/GHSA-fw8g-cg8f-9j28
- https://security-tracker.debian.org/tracker/CVE-2026-44903
CWEs
CWE-79
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.