CVE-2025-45765Network attack vector

Signature compromise via unenforced JWS key lengths

Published Aug 7, 2025 · Updated Aug 12, 2025

Insufficient key strength in ruby-jwt allows remote attackers to compromise JWS signatures created with undersized HMAC or RSA keys. The JWS signing and verification paths accept keys without enforcing minimum lengths, leaving key strength to the application and OpenSSL. Reachability requires an application to select an undersized key; the supplier disputes that key-size policy belongs in the library.

CVSS severity9.1
Critical
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient key strength in ruby-jwt allows remote attackers to compromise JWS signatures created with undersized HMAC or RSA keys. The JWS signing and verification paths accept keys without enforcing minimum lengths, leaving key strength to the application and OpenSSL. Reachability requires an application to select an undersized key; the supplier disputes that key-size policy belongs in the library.

The record

CVE
CVE-2025-45765
Published
Aug 7, 2025
Updated
Aug 12, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-326, CAPEC-192, CAPEC-20, CAPEC-112
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 7, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-326Inadequate Encryption Strength
CAPEC-192Protocol Analysis
CAPEC-20Encryption Brute Forcing
CAPEC-112Brute Force

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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