CVE-2024-25714Network attack vector

HMAC verification timing leak via early-exit comparison

Published Feb 11, 2024 · Updated Aug 1, 2024

Timing side channel in Rhonabwy 1.1.13 and earlier allows remote attackers to infer HMAC comparison progress during JWS verification. The r_jws_verify_sig_hmac function in src/jws.c compares supplied and computed Base64url signatures with an early-exit string comparison instead of constant-time logic. Repeated access to an application exposing HMAC verification is required, and response timing serves as an oracle for signature guesses rather than directly exposing payload data.

CVSS severity9.8
Critical
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in Rhonabwy 1.1.13 and earlier allows remote attackers to infer HMAC comparison progress during JWS verification. The r_jws_verify_sig_hmac function in src/jws.c compares supplied and computed Base64url signatures with an early-exit string comparison instead of constant-time logic. Repeated access to an application exposing HMAC verification is required, and response timing serves as an oracle for signature guesses rather than directly exposing payload data.

The record

CVE
CVE-2024-25714
Published
Feb 11, 2024
Updated
Aug 1, 2024
Vendor
Babelouest
Product
Rhonabwy
Classifications
CWE-1255, CWE-203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <=1.1.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Babelouest · Rhonabwyversion=0 <=1.1.13

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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-1255Comparison Logic is Vulnerable to Power Side-Channel Attacks
CWE-203Observable Discrepancy

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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