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Example RSS reader rule could allow for a targeted bypass of Anubis when used to protect frameworks like Rails

Moderate
Xe published GHSA-2c93-xxqg-54gm Mar 21, 2025

Package

docker Anubis (Docker)

Affected versions

< v1.14.2

Patched versions

v1.14.2

Description

Impact

The default ruleset has the following entry:

    {
      "name": "rss-readers",
      "path_regex": ".*\\.(rss|xml|atom|json)$",
      "action": "ALLOW"
    },

The intent of this rule was to allow for RSS readers to work with my blog in particular.

Frameworks like Rails will treat these specially, meaning that going to /things/12345-whateverhaha.json could bypass Anubis.

If your webapp doesn't use a framework with slug resolution rules like that, this is not a security risk.

Patches

v1.14.2 fixes this issue for the default configuration.

Workarounds

Anyone with a custom bot policy file is unaffected.

References

See #67 for more information.

Credits

Thanks Graham Sutherland for reporting this over email.

Severity

Moderate

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
Unchanged
Confidentiality
Low
Integrity
None
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:U/C:L/I:N/A:N

CVE ID

No known CVE

Weaknesses

No CWEs