CVE-2026-21858 in the critical feed json
n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling
published 10mo ago modified 4mo ago also EUVD-2026-1187 , GHSA-v4pr-fm98-w9pg
- cvss
- 10.0
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 78.2%
- EPSS 78.2% chance of exploitation in 30 days, percentile 99.5%
- public exploits
- 0
- none known, plus a Nuclei check
Summary
n8n is an open source workflow automation platform. Versions starting with 1.65.0 and below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0.
Patch / fix
- npm n8n 1.121.0
- n8n n8n 1.121.0
Is CVE-2026-21858 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 10mo ago
Exploit prediction
78.19% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- Nuclei template n8n Webhooks - Remote Code Execution nuclei detection template
- cyera.com https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | n8n | >=1.65.0, <1.121.0 |
1.121.0 |
Affected products
- n8n-io n8n
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
cyera.com
/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858
web, exploit, third-party-advisory
-
github.com
/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-21858
advisory
-
github.com
/n8n-io/n8n
package
Sources
- CVE List CVE-2026-21858
- GitHub Advisory GHSA-v4pr-fm98-w9pg
- NVD CVE-2026-21858
Fencer Intel 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.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.