VulnerabilityPublished 29 Oct 2026

CVE-2026-114620: Authlib · Unvalidated request_uri fetch in JWT-secured authorization request (JAR) leading to SSRF

Affects kaskadeSource GCVE Database

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Authoritative record:CVE-2026-114620· Medium 5.4

Not known to be exploited · CVSS 5.4 Medium.

Data as of 30 Oct 2026, 08:44 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	5.4

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Homebrewkaskade`pkg:brew/kaskade`Other threats	Affected >=4.0.4_1	Fixed in–

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AI-suggested

As of the provided information, no explicit patch or fix is documented. Users should not implement the documented example fetch hook that performs an unrestricted HTTP GET on the 'request_uri'. Instead, they must enforce validation of 'request_uri' values against the client metadata 'request_uris' allowlist and the server metadata 'require_request_uri_registration' flag before fetching. Additionally, implement controls recommended by RFC 9101 §10.4.1, including verifying the response media type, enforcing timeouts, and preventing recursive fetches. Until an official fix is available, integrators should override the 'get_request_object()' method to safely validate and restrict outbound requests. Monitor vendor advisories for official patches or updates.

Description

Authlib's implementation of the RFC 9101 JWT-secured authorization request (JAR) extension contains a security flaw where the attacker-controlled 'request_uri' parameter is passed to a fetch hook without validation at a pre-authentication endpoint. Although Authlib defines allowlists for 'request_uris' and requires registration, these controls are not enforced in the extension. The documented example implementation performs an unrestricted HTTP GET request on the 'request_uri', resulting in an unauthenticated Server-Side Request Forgery (SSRF) vulnerability. This flaw was verified in Authlib version 1.7.2 and the current main branch. The vulnerability allows attackers to induce the server to make arbitrary HTTP requests, potentially exposing internal resources.

Impact

An attacker can exploit this vulnerability to perform unauthenticated SSRF attacks by supplying a malicious 'request_uri' parameter in authorization requests. This can lead to unauthorized internal network scanning, access to sensitive internal services or metadata endpoints, and potential information disclosure. The vulnerability exists because the extension does not enforce existing allowlists or implement recommended security controls, and the documented example encourages insecure usage. The CVSS 3.1 base score is 5.4 (medium severity) reflecting network attack vector, high attack complexity, no privileges required, no user interaction, and partial confidentiality and integrity impact.

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Description

AI analysisMachine-generated, updated 30 Oct 2026, 08:44 UTC

Technical details

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