Alertmanager UI is vulnerable to stored XSS via the /api/v1/alerts endpoint

CVE-2023-40577 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Impact

An attacker with the permission to perform POST requests on the /api/v1/alerts endpoint could be able to execute arbitrary JavaScript code on the users of Prometheus Alertmanager.

Patches

Users can upgrade to Alertmanager v0.2.51.

Workarounds

Users can setup a reverse proxy in front of the Alertmanager web server to forbid access to the /api/v1/alerts endpoint.

References

N/A

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2023-08-23 20:42:43 UTC
Updated
2023-11-12 05:02:24 UTC
GitHub reviewed
2023-08-23 20:42:43 UTC
NVD published
2023-08-24

EPSS Score

Score Percentile
3.58% 87.53%

CVSS Scores

Base score Version Severity Vector
5.4 3.1 —
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-v86x-5fm3-5p7j ↗
CVE CVE-2023-40577 ↗

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credits

  • oxeye-gal (reporter)
  • oxeye-daniel (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/prometheus/alertmanager <= 0.25.0 0.25.1 —

References

cvelogic Threat Intelligence