vulnerability / NVI-00012035 / Revision 2
Prometheus has Stored XSS via metric names and label values in Prometheus web UI tooltips and metrics explorer
GitHub lists this reviewed advisory for github.com/prometheus/prometheus, github.com/prometheus/prometheus, github.com/prometheus/prometheus. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.1 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.259%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.17672. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/prometheus/prometheus
source listed>= 3.0.0, <= 3.5.1
### Impact Stored cross-site scripting (XSS) via crafted metric names in the Prometheus web UI: * **Old React UI + New Mantine UI:** When a user hovers over a chart tooltip on the Graph page, metric names containing HTML/JavaScript are injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user opens the Metric Explorer (globe icon next to the PromQL expression input field), and a metric name containing HTML/JavaScript is rendered in the fuzzy search results, it is injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user views a heatmap chart and hovers over a cell, the `le` label values of the underlying histogram buckets are interpolated into `innerHTML` without escaping. While `le` is conventionally a numeric bucket boundary, Prometheus does not enforce this — arbitrary UTF-8 strings are accepted as label values, allowing script injection via a crafted scrape target or remote write. With Prometheus v3.x defaulting to UTF-8 metric and label name validation, characters like ``, and `"` are now valid in metric name
github.com/prometheus/prometheus
source listed>= 3.6.0, <= 3.11.1
### Impact Stored cross-site scripting (XSS) via crafted metric names in the Prometheus web UI: * **Old React UI + New Mantine UI:** When a user hovers over a chart tooltip on the Graph page, metric names containing HTML/JavaScript are injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user opens the Metric Explorer (globe icon next to the PromQL expression input field), and a metric name containing HTML/JavaScript is rendered in the fuzzy search results, it is injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user views a heatmap chart and hovers over a cell, the `le` label values of the underlying histogram buckets are interpolated into `innerHTML` without escaping. While `le` is conventionally a numeric bucket boundary, Prometheus does not enforce this — arbitrary UTF-8 strings are accepted as label values, allowing script injection via a crafted scrape target or remote write. With Prometheus v3.x defaulting to UTF-8 metric and label name validation, characters like ``, and `"` are now valid in metric name
github.com/prometheus/prometheus
source listed< 0.311.2-0.20260410083055-07c6232d159b
### Impact Stored cross-site scripting (XSS) via crafted metric names in the Prometheus web UI: * **Old React UI + New Mantine UI:** When a user hovers over a chart tooltip on the Graph page, metric names containing HTML/JavaScript are injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user opens the Metric Explorer (globe icon next to the PromQL expression input field), and a metric name containing HTML/JavaScript is rendered in the fuzzy search results, it is injected into `innerHTML` without escaping, causing arbitrary script execution in the user's browser. * **Old React UI only:** When a user views a heatmap chart and hovers over a cell, the `le` label values of the underlying histogram buckets are interpolated into `innerHTML` without escaping. While `le` is conventionally a numeric bucket boundary, Prometheus does not enforce this — arbitrary UTF-8 strings are accepted as label values, allowing script injection via a crafted scrape target or remote write. With Prometheus v3.x defaulting to UTF-8 metric and label name validation, characters like ``, and `"` are now valid in metric name
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-vffh-x6r8-xx99 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-40179 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.