CVE-2024-31033Network attack vector

Overestimated HMAC key strength via ignored characters

Published Apr 1, 2024 · Updated Aug 27, 2024

Improper key handling in JWTK JJWT 0.12.5 and earlier allows applications to accept weaker-than-expected HMAC keys. The reported setSigningKey() and signWith() paths decode string key material while ignoring certain characters, so apparent text length can overstate the effective key bytes. The condition requires application-supplied string key material; JWTK disputes that supported versions can exhibit it, and GitHub withdrew the advisory.

CVSS severity6.8
Medium
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper key handling in JWTK JJWT 0.12.5 and earlier allows applications to accept weaker-than-expected HMAC keys. The reported setSigningKey() and signWith() paths decode string key material while ignoring certain characters, so apparent text length can overstate the effective key bytes. The condition requires application-supplied string key material; JWTK disputes that supported versions can exhibit it, and GitHub withdrew the advisory.

The record

CVE
CVE-2024-31033
Published
Apr 1, 2024
Updated
Aug 27, 2024
Vendor
JWTK
Product
JJWT
Classifications
CWE-327
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=0.12.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JWTK · JJWTversion=0 <=0.12.5

Published CVSS scores

6.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-327Use of a Broken or Risky Cryptographic Algorithm

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo