VulnerabilityPublished 1 Apr 2024Updated 27 Aug 2024

CVE-2024-31033: jjwt

Affects jjwtSource CVE Database V5

Not known to be exploited · CVSS 6.8 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.8Medium

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
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: 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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 1 Apr 2024
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

Affected software

Product	Affected	Fixed in
Mavenio.jsonwebtoken/jjwt`pkg:maven/io.jsonwebtoken/jjwt`Other threats	Affected <=0.12.5	Fixed in–

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AI-suggested

Organizations should ensure they are using the latest stable version of the JJWT library, as the vendor indicates that the vulnerability does not exist in current versions. Developers must carefully validate and sanitize cryptographic keys used for JWT signing and verification to avoid user errors that could lead to ignored characters. Implement strict key management policies, including using keys of sufficient length and complexity, and avoid deprecated or outdated library versions. Conduct thorough code reviews and security testing focused on JWT handling and key usage. Additionally, consider implementing defense-in-depth measures such as token expiration, audience validation, and signature verification using multiple factors. Monitoring for unusual authentication patterns and anomalies in token usage can also help detect potential exploitation attempts.

Description

JJWT (aka Java JWT) through 0.12.5 ignores certain characters and thus a user might falsely conclude that they have a strong key. The impacted code is the setSigningKey() method within the DefaultJwtParser class and the signWith() method within the DefaultJwtBuilder class. NOTE: the vendor disputes this because the "ignores" behavior cannot occur (in any version) unless there is a user error in how JJWT is used, and because the version that was actually tested must have been more than six years out of date.

Impact

If exploited, this vulnerability could allow attackers to compromise the confidentiality and integrity of JWT tokens by exploiting weak or improperly handled signing keys. Attackers might craft tokens that bypass authentication or authorization controls if the signing key is effectively weaker than assumed. This can lead to unauthorized access to protected resources, data leakage, or privilege escalation in applications relying on JJWT for token-based authentication. Since JWTs are widely used for securing APIs and web services, the impact could be significant for organizations that do not properly validate or manage their signing keys. However, the requirement for user interaction and high attack complexity reduces the likelihood of widespread exploitation. The absence of known exploits in the wild further suggests limited immediate risk, but the potential impact on confidentiality and integrity remains notable.

References

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