TI-2026-32778 Aliases CVE-2026-44903 GHSA-fw8g-cg8f-9j28

Prometheus: Stored XSS via crafted histogram bucket label values in the heatmap display of the old Prometheus web UI

LOW 23CWE-79Published 2026-05-26 · Updated 2026-05-27

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Cross-site scripting
Confidentiality · integrity · availability: None · None · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00204 10th percentileScored 2026-11-07

Fix Fixed prometheus (prometheus): 3.5.3, 3.11.3github.com/prometheus/prometheus (Go): 0.311.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
prometheus	prometheus	2.49.0 to before 3.5.3; 3.6.0-rc.0 to before 3.11.3	3.5.3, 3.11.3	Patch available	CNA
—	github.com/prometheus/prometheus (Go)	before 0.311.3	0.311.3	Patch available	GHSA-fw8g-cg8f-9j28

prometheus Vendorprometheus Affected 2.49.0 to before 3.5.3; 3.6.0-rc.0 to before 3.11.3 Fixed in 3.5.3, 3.11.3 Patch available CNA
github.com/prometheus/prometheus (Go) Vendor— Affected before 0.311.3 Fixed in 0.311.3 Patch available GHSA-fw8g-cg8f-9j28

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:prometheus:prometheus::::::::	2.49.0 to before 3.5.3; 3.6.0 to before 3.11.3	Vulnerable	prometheus

cpe:2.3:a:prometheus:prometheus:*:*:*:*:*:*:*:* Versions 2.49.0 to before 3.5.3; 3.6.0 to before 3.11.3 Vulnerable ·prometheus

Remediation

Fix · CNA prometheus (prometheus) Fixed in 3.5.3, 3.11.3
Fix · GHSA-fw8g-cg8f-9j28 github.com/prometheus/prometheus (Go) Fixed in 0.311.3 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-44903
2026-10-03 Alias added: GHSA-fw8g-cg8f-9j28

References

Patch 2

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-44903

Other 1

https://github.com/prometheus/prometheus

TI-2021-10330 Arbitrary redirects under /new endpoint CVSS 3.1MEDIUM 6.5
TI-2026-30483 Prometheus: remote read endpoint allows denial of service via crafted snappy payload CVSS 3.1HIGH 7.5
TI-2026-30481 Prometheus Azure AD remote write OAuth client secret exposed via config API CVSS 3.1HIGH 7.5
TI-2019-02838 Cross-site scripting in [UNKNOWN] prometheus CVSS 3.0MEDIUM 6.1
TI-2026-28993 Prometheus: Stored XSS via metric names and label values in web UI tooltips and metrics explorer CVSS 4.0MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences