VulnerabilityPublished 11 Jul 2025Updated 23 Sep 2025

CVE-2025-53864: Connect2id Nimbus JOSE+JWT · Uncontrolled Recursion

Affects Connect2id Nimbus JOSE+JWTSource CVE Database V5

Not known to be exploited · CVSS 5.8 Medium : upgrade to 10.0.2 or 9.37.4 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

5.8Medium

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

EPSS: 0.9% chance of exploitation in 30 days – higher than 61% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 10.0.2, 9.37.4

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

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

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: 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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 com.nimbusds/nimbus-jose-jwt to 10.0.2 or 9.37.4.

Affected software

Product	Affected	Fixed in
Mavencom.nimbusds/nimbus-jose-jwt`pkg:maven/com.nimbusds/nimbus-jose-jwt`Other threats	Affected <9.37.4 <10.0.2	Fixed in 9.37.4 10.0.2

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

AI-suggested

European organizations should take immediate steps to mitigate this vulnerability beyond generic advice. First, identify all applications and services using the Connect2id Nimbus JOSE+JWT library, focusing on versions prior to 10.0.2 and 9.37.4. If patches are not yet released, implement compensating controls such as input validation to limit the depth of JSON objects within JWT claim sets before processing. This can be done by enforcing strict schema validation or using custom JSON parsers that impose nesting limits. Additionally, deploy Web Application Firewalls (WAFs) or API gateways with rules to detect and block JWTs containing suspiciously deep or complex JSON structures. Monitoring and alerting on unusual JWT payload sizes or parsing errors can help detect exploitation attempts early. Rate limiting JWT validation requests can reduce the risk of resource exhaustion from repeated attacks. Finally, conduct thorough code reviews and security testing on JWT handling components to ensure no other uncontrolled recursion or resource exhaustion vulnerabilities exist. Document and update incident response plans to include scenarios involving JWT-based denial of service attacks.

Description

Connect2id Nimbus JOSE + JWT 10.0.x before 10.0.2 and 9.37.x before 9.37.4 allows a remote attacker to cause a denial of service via a deeply nested JSON object supplied in a JWT claim set, because of uncontrolled recursion. NOTE: this is independent of the Gson 2.11.0 issue because the Connect2id product could have checked the JSON object nesting depth, regardless of what limits (if any) were imposed by Gson.

Impact

For European organizations, the primary impact of this vulnerability is the risk of denial of service in applications or services that rely on the Connect2id Nimbus JOSE+JWT library for JWT processing. Since JWTs are widely used for authentication and authorization in web applications, APIs, and microservices, exploitation could disrupt critical identity and access management workflows. This could lead to service outages, degraded user experience, and potential operational disruptions, especially in sectors relying heavily on federated identity or OAuth/OIDC protocols. Although the vulnerability does not compromise confidentiality or integrity, the availability impact can be significant in environments where uptime and continuous access are critical, such as financial services, healthcare, government portals, and telecommunications. Additionally, denial of service attacks can be leveraged as part of larger multi-vector attacks or to distract security teams. The lack of required authentication or user interaction means that attackers can exploit this remotely and anonymously, increasing the threat surface. European organizations with public-facing services or APIs that accept JWTs generated or processed by vulnerable versions of Nimbus JOSE+JWT are at risk. The impact is heightened in environments with high transaction volumes or where JWT validation is a frequent operation, as the resource exhaustion can be triggered repeatedly to amplify the denial of service effect.

CWE-674Uncontrolled Recursion (opens in a new tab)
Class weakness
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
Implementation
Ensure that an end condition will be reached under all logic conditions. The end condition may include checking against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.
Implementation
Increase the stack size.
Attack patterns
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Sep 2025, 00:19 UTC

WeaknessesCWE-674

Technical details

References

Community reviews

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