GHSA-fw8g-cg8f-9j28Published

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

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cve-program · CVE-2026-44903

Published

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 published: 26 May 2026 21:27:18 UTC
Source modified: 27 May 2026 14:20:35 UTC
Saved here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

euvd · EUVD-2026-32008

Published

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

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datePublished: May 26, 2026, 9:27:18 PM

dateUpdated: May 27, 2026, 2:20:35 PM

1 related source bulletins · separate from aliases

WID-SEC-W-2026-1292: Prometheus: Mehrere Schwachstellen

CVE-2026-42151 · CVE-2026-42154 · CVE-2026-44903

Source published: May 26, 2026, 9:27:18 PM (timezone not stated)
Source modified: May 27, 2026, 2:20:35 PM (timezone not stated)
Saved here: 13 Nov 2026 13:02:40 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 4.0 · 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

nvd · CVE-2026-44903

Published

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-79

Original publisher date fields

published: 2026-05-26T22:16:43.010

lastModified: 2026-07-24T12:10:00.210

1 source CPE criteria · context only

cpe:2.3:a:prometheus:prometheus:*:*:*:*:*:*:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 26 May 2026 22:16:43 UTC
Source modified: 24 Jul 2026 12:10:00 UTC
Saved here: 25 Oct 2026 10:17:27 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · [email protected] · Secondary · 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

osv · GHSA-fw8g-cg8f-9j28

Published

### 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 compromised scrape target, remote write, or OTLP receiver endpoint) can execute JavaScript in the browser of any Prometheus user who views the metric in the heatmap chart UI. From the XSS context, an attacker could for example: - Read `/api/v1/status/config` to extract sensitive configuration (although credentials / secrets are redacted by the server) - Call `/-/quit` to shut down Prometheus (only if `--web.enable-lifecycle` is set) - Call `/api/v1/admin/tsdb/delete_series` to delete data (only if `--web.enable-admin-api` is set) - Exfiltrate metric data to an external server Note that this only affects users who have explicitly enabled the legacy Prometheus web UI using the `--enable-feature=old-ui` command-line flag. ### Patches https://github.com/prometheus/prometheus/commit/38f23b9075ced1de2b82d2dad8b2bebb1ecd5b7d ### Workarounds If at all possible, disable the legacy web UI by removing the `--enable-feature=old-ui` command-line flag). If this is not an option, take the following precautions: - If using the remote write receiver (`--web.enable-remote-write-receiver`), ensure it is not exposed to untrusted sources. - If using the OTLP receiver (`--web.enable-otlp-receiver`), ensure it is not exposed to untrusted sources. - Ensure scrape targets are trusted and not under attacker control. - Do not enable admin / mutating API endpoints (e.g. `--web.enable-admin-api` or `web.enable-lifecycle`) in cases where you cannot prevent untrusted data from being ingested. - Users should avoid clicking untrusted links, especially those containing functions such as `label_replace`, as they may generate poisoned label names and values. ### References - CVE-2019-10215 — prior stored DOM XSS vulnerability in Prometheus query history, fixed in v2.7.2 - CVE-2026-40179 — prior stored DOM XSS vulnerability in Prometheus web UI (hover tooltips and metrics explorer), fixed in v3.11.2

Source published: 5 May 2026 21:53:18 UTC
Source modified: 10 Sep 2026 03:51:05 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Publisher rating · MODERATE

osv · GO-2026-5381

Published

Prometheus vulnerable to stored XSS via crafted histogram bucket label values in the old web UI heatmap display in github.com/prometheus/prometheus

Source published: 25 Jun 2026 18:43:19 UTC
Source modified: 27 Jun 2026 18:29:24 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.