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Fencer Vulns
high 7.5

CVE-2023-40577 json

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

published 2023-08-23 3 y ago modified 2026-09-10 59 d ago also BIT-alertmanager-2023-40577 , EUVD-2023-2358 , GHSA-v86x-5fm3-5p7j , GO-2023-2020

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Alertmanager handles alerts sent by client applications such as the Prometheus server. 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. This issue has been fixed in Alertmanager version 0.2.51.

Patch / fix

  • go github.com/prometheus/alertmanager 0.25.1
  • bitnami alertmanager 0.25.1
  • prometheus-alertmanager Debian 14, Debian 13 0.26.0+ds-1

debian advisories DEBIAN-CVE-2023-40577

  • prometheus-alertmanager Ubuntu 20.04 LTS 0.15.3+ds-3ubuntu1.2
  • prometheus-alertmanager Ubuntu Pro 18.04 LTS 0.6.2+ds-3ubuntu0.1+esm1
  • prometheus-alertmanager Ubuntu Pro 22.04 LTS 0.23.0-4ubuntu0.2+esm1

ubuntu advisories UBUNTU-CVE-2023-40577

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • golang-github-prometheus-alertmanager SLE Module for Package Hub 15 SP5, openSUSE Leap 15.5, Manager Proxy Module 4.3 +1 more 0.26.0-150100.4.19.1
  • grafana Manager Client Tools 12 9.5.8-1.60.1
  • spacecmd Manager Client Tools 12 4.3.26-38.136.2
  • mgr-daemon Manager Client Tools 12 4.3.8-1.44.2
  • spacewalk-client-tools Manager Client Tools 12 4.3.18-52.95.2
  • prometheus-postgres_exporter Manager Client Tools 12 0.10.1-1.17.2
  • golang-github-prometheus-prometheus Manager Client Tools 12 2.45.0-1.50.2
  • golang-github-prometheus-alertmanager Manager Client Tools 12 0.26.0-1.24.2

suse advisories SUSE-SU-2024:0512-1SUSE-SU-2024:0486-1SUSE-SU-2024:0191-1

  • golang-github-prometheus-alertmanager openSUSE Tumbleweed 0.26.0-4.1

opensuse advisories openSUSE-SU-2024:13599-1

  • alertmanager Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 0.26.0-r0

alpine advisories ALPINE-CVE-2023-40577

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-40577 updated cvss 7.5

prometheus-alertmanager: UI is vulnerable to stored XSS via the /api/v1/alerts endpoint

  • Red Hat OpenShift Container Platform 4.15 openshift4/ose-prometheus-alertmanager v4.15.0-202401290854.p0.g870ade5.assembly.stream
    fixed: vendor fix “Users can setup a reverse proxy in front of the Alertmanager web server to forbid access to the /api/v1/alerts endpoint.” RHSA-2023:7198
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/prometheus-alertmanager-rhel8 Red Hat OpenShift Container Platform 3.11 prometheus-alertmanager, openshift3/prometheus-alertmanager, golang-github-prometheus-alertmanager Red Hat OpenShift Container Platform 4.15 rhcos 415.92.202402201450-0, openshift4/ose-cli v4.15.0-202402082307.p0.g48dcf59.assembly.stream.el8, openshift4/ose-tests v4.15.0-202402210808.p0.gb71aeaf.assembly.stream.el8, openshift4/ose-etcd-rhel9 v4.15.0-202401261531.p0.g5acb4f3.assembly.stream, openshift4/ose-prometheus v4.15.0-202401290854.p0.g6828e44.assembly.stream, openshift4/ose-console v4.15.0-202402151637.p0.g803df88.assembly.stream.el8, +188 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/prometheus/alertmanager
<0.25.1
0.25.1
bitnami alertmanager
>=0.25.0, <0.25.1
0.25.1

Affected products

  • prometheus alertmanager

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.