CVE-2026-39087Network attack vector

Authenticated SSRF via unanchored endpoint allowlist

Published Apr 23, 2026 · Updated Apr 23, 2026

SSRF in ntfy before 2.22.0 allows remote authenticated users to make server-side HTTP requests via crafted web push endpoint URLs. The web push endpoint allowlist uses an unanchored regular expression, so an allowed-looking substring can conceal an arbitrary destination. A low-privileged account can thereby probe or interact with internal and arbitrary external HTTP services from the server's network context.

CVSS severity6.4
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SSRF in ntfy before 2.22.0 allows remote authenticated users to make server-side HTTP requests via crafted web push endpoint URLs. The web push endpoint allowlist uses an unanchored regular expression, so an allowed-looking substring can conceal an arbitrary destination. A low-privileged account can thereby probe or interact with internal and arbitrary external HTTP services from the server's network context.

The record

CVE
CVE-2026-39087
Published
Apr 23, 2026
Updated
Apr 23, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, CWE-777, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.4MITRECVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-777Regular Expression without Anchors
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo