VulnerabilityPublished 13 Aug 2026Updated 29 Oct 2026

CVE-2026-41425: Authlib · Cross-site request forging when using cache

Affects mcp-atlassianSource GCVE Database

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Not known to be exploited · CVSS 5.4 Medium : upgrade to 0.21.1_2 when convenient.

Data as of 30 Oct 2026, 08:32 UTC

CVSS 3.1 base score

5.4Medium

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

Patch: Available – fixed in 0.21.1_2

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
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 13 Aug 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

Upgrade mcp-atlassian to 0.21.1_2.

Affected software

Product	Affected	Fixed in
Homebrewmcp-atlassian`pkg:brew/mcp-atlassian`Other threats	Affected >=0.11.11 <0.21.1_2	Fixed in 0.21.1_2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in Authlib version 0.21.1_2 that addresses this CSRF vulnerability. Users should upgrade to version 0.21.1_2 or later. Until upgraded, users should avoid using the cache parameter for OAuth state storage or implement additional CSRF protections as a temporary measure.

Description

Authlib versions from 0.11.11 up to but not including 0.21.1_2 have a CSRF vulnerability in their OAuth integrations when using the cache parameter. The cache-based state management lacks CSRF protection, allowing an attacker to forge authorization requests that tie the victim to the attacker's account. This issue affects multiple integration clients, including Starlette, and is fixed in version 0.21.1_2.

Impact

Users of Authlib who rely on the cache parameter for OAuth state storage are vulnerable to cross-site request forgery (CSRF) attacks. An attacker can cause a victim to complete an authorization flow that links the victim's session to the attacker's account, potentially leading to unauthorized access or session confusion. The CVSS 3.1 base score is 5.4 (medium severity), reflecting low confidentiality and integrity impact with no availability impact.

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Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 08:32 UTC

Technical details

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