CVE-2025-54887VulnerabilityPublished 8 Aug 2025

CVE-2025-54887: jwt ruby-jwe · Improper Validation of Integrity Check Value

Affects jwt ruby-jweSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical : upgrade to 1.1.1 as a priority.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

9.1Critical

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.1.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
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: 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: 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 8 Aug 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 2026-10-26.

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 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 jwt ruby-jwe to 1.1.1.

Affected software

Product	Affected	Fixed in
jwt ruby-jwe	Affected <1.1.1	Fixed in 1.1.1

AI-suggested

European organizations should immediately upgrade ruby-jwe to version 1.1.1 or later to remediate this vulnerability. Beyond patching, it is crucial to rotate all encryption keys used with ruby-jwe to invalidate any potentially compromised GHASH keys. Organizations should audit their codebases and dependencies to identify all instances of ruby-jwe usage, including transitive dependencies in Ruby gems. Implement strict cryptographic hygiene by enforcing key management best practices, such as using hardware security modules (HSMs) or secure key vaults for key storage and rotation. Conduct thorough testing to ensure that token validation and encryption behave correctly after the upgrade. Monitor application logs and network traffic for anomalous JWE parsing errors or repeated failed authentication tag validations, which may indicate exploitation attempts. Additionally, consider implementing layered security controls such as Web Application Firewalls (WAFs) with rules to detect and block malformed or suspicious JWE tokens. Finally, update incident response plans to include this vulnerability and train security teams on its detection and mitigation.

Description

jwe is a Ruby implementation of the RFC 7516 JSON Web Encryption (JWE) standard. In versions 1.1.0 and below, authentication tags of encrypted JWEs can be brute forced, which may result in loss of confidentiality for those JWEs and provide ways to craft arbitrary JWEs. This puts users at risk because JWEs can be modified to decrypt to an arbitrary value, decrypted by observing parsing differences and the GCM internal GHASH key can be recovered. Users are affected by this vulnerability even if they do not use an AES-GCM encryption algorithm for their JWEs. As the GHASH key may have been leaked, users must rotate the encryption keys after upgrading. This issue is fixed in version 1.1.1.

Impact

For European organizations, the impact of CVE-2025-54887 is substantial. Many enterprises and public sector entities in Europe use Ruby-based web applications and services that may incorporate ruby-jwe for secure token encryption. Exploitation could lead to unauthorized disclosure of sensitive information, such as personally identifiable information (PII), financial data, or authentication credentials, violating GDPR and other data protection regulations. The ability to forge arbitrary JWEs also undermines trust in authentication and authorization mechanisms, potentially enabling privilege escalation or impersonation attacks. This could disrupt business operations, damage reputations, and result in regulatory penalties. Critical infrastructure and government services relying on Ruby applications are particularly at risk. The vulnerability’s ease of exploitation without authentication or user interaction increases the likelihood of targeted attacks or automated scanning by threat actors. Even organizations not directly using AES-GCM are affected, broadening the scope of impact. The need to rotate encryption keys post-upgrade adds operational complexity and risk during remediation.

CWE-354Improper Validation of Integrity Check Value (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product does not validate or incorrectly validates the integrity check values or "checksums" of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission.
Implementation
Ensure that the checksums present in messages are properly checked in accordance with the protocol specification before they are parsed and used.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
Attack patterns
Checksum Spoofing (opens in a new tab)
Padding Oracle Crypto Attack (opens in a new tab)
Manipulating Writeable Configuration Files (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Aug 2025, 01:13 UTC

WeaknessesCWE-354

Technical details

References

Community reviews

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