CVE-2026-39087 ntfy.sh allows a remote attacker to execute arbitrary code via the parseActions function
Attackers can exploit an unanchored regex in ntfy to perform Server-Side Request Forgery, potentially accessing internal resources.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39087?
CVE-2026-39087 is a medium-severity server-side request forgery vulnerability in ntfy, published on 23 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
ntfy before 2.22.0 allows SSRF because of an unanchored regular expression for web push endpoint URLs.
Which versions are affected by CVE-2026-39087?
4 open source packages ship an affected version, including heckel.io/ntfy/v2 and heckel.io/ntfy.
| Package | Affected | Fixed in |
|---|---|---|
heckel.io/ntfy/v2 Go | All versions | 2.22.0 |
heckel.io/ntfy/v2 Go | All versions | 2.22.0 |
heckel.io/ntfy/v2 Go | All versions | 2.22.0 |
heckel.io/ntfy Go | All versions | None |
How do I fix CVE-2026-39087?
Upgrade heckel.io/ntfy/v2 to 2.22.0 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-39087 being exploited?
There is no known exploitation of CVE-2026-39087 in the wild and no public exploit code.
Sources
Also known as GHSA-pqhx-w72w-m393, GO-2026-5551, UBUNTU-CVE-2026-39087.