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Nautobot: Webhook definitions could be used for server-side request forgery (SSRF)

High severity GitHub Reviewed Published May 8, 2026 in nautobot/nautobot • Updated May 13, 2026

Package

pip nautobot (pip)

Affected versions

>= 3.0.0a2, < 3.1.2
< 2.4.33

Patched versions

3.1.2
2.4.33

Description

Impact

Nautobot's Webhook data model and associated feature set could be configured by users with sufficient access to perform requests to various hosts and IP addresses that should not be permitted, allowing for various behaviors similar to server-side request forgery (SSRF).

Patches

Fixes are available in Nautobot v2.4.33 and v3.1.2.

In support of this fix, three new settings variables have been added to Nautobot:

  • WEBHOOK_ALLOWED_SCHEMES - By default new or updated Webhook records will be restricted to HTTP or HTTPS only, disallowing other schemes that may have been previously allowed. Administrators should audit existing Webhook records to identify any that are invalid, and either update/delete said records or customize WEBHOOK_ALLOWED_SCHEMES as appropriate.
  • WEBHOOK_ADDITIONAL_BLOCKED_NETWORKS - This can be used to specify additional IP networks that should be denied to Webhook sending, for example some deployments may wish to disallow RFC1918 addresses or even disallow all networks and carve out specific exemptions using the following setting.
  • WEBHOOK_ALLOWED_HOSTS - This can be used to provide an allow-list of specific hosts that would otherwise be blocked by any WEBHOOK_ADDITIONAL_BLOCKED_NETWORKS configuration.

Workarounds

Administrators should review which users have been granted add or change permissions for the Webhook data model, and should review currently defined Webhook records for safety and validity. Other than that, no specific workaround has been identified.

References

References

@glennmatthews glennmatthews published to nautobot/nautobot May 8, 2026
Published to the GitHub Advisory Database May 13, 2026
Reviewed May 13, 2026
Last updated May 13, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS score

Weaknesses

Server-Side Request Forgery (SSRF)

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Learn more on MITRE.

CVE ID

CVE-2026-44797

GHSA ID

GHSA-c35q-vxrp-ph26

Source code

Credits

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