Security Digest · Vulnerability record
CVE-2026-39087: ntfy.sh allows a remote attacker to execute arbitrary code via the parseActions function
ntfy before 2.22.0 allows SSRF because of an unanchored regular expression for web push endpoint URLs.
CVSS 6.4 Medium EPSS 0.5% · p41
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
heckel.io/ntfy/v2(Go) < 2.22.0, fixed in 2.22.0. Check your lockfile, including transitive dependencies.
What it is
ntfy before 2.22.0 allows SSRF because of an unanchored regular expression for web push endpoint URLs.
From the GitHub advisory
An issue in Ntfy ntfy.sh before v.2.22.0 allows a remote attacker to execute arbitrary code via the parseActions function.
Weakness type: CWE-777, CWE-94.
Product: heckel.io/ntfy/v2 (Go) · Assigned by: mitre · Published: 2026-04-23
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | heckel.io/ntfy/v2 | < 2.22.0 | 2.22.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| ntfy | ntfy | < 2.22.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| mitre | 3.1 | 6.4 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| CISA-ADP | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 41.
Timeline
- — CVE record published by mitre
- — GitHub-reviewed advisory GHSA-pqhx-w72w-m393 published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-pqhx-w72w-m393 github.com
- CVE.org record CVE-2026-39087 cve.org
- NVD entry CVE-2026-39087 nvd.nist.gov
Other references from the CVE record and advisory
- gist.github.com gist.github.com
- github.com github.com
- ntfy.sh ntfy.sh
- ntfy.com ntfy.com
- ntfysh.com ntfysh.com