CVE-2021-4259Network attack vector

Authentication bypass via loose digest comparison

Published Dec 19, 2022 · Updated Aug 3, 2024

Authentication bypass in Erik Dubbelboer's phpRedisAdmin 1.16.0 through 1.16.1 allows remote attackers to access Redis via HTTP Digest. The authHttpDigest function in includes/login.inc.php loosely compares the supplied response with an MD5 digest, allowing magic-hash strings treated as numeric zero to compare equal. Exploitation requires HTTP Digest authentication and a crafted response reaching that comparison, after which Redis data can be read, changed, or deleted through the interface.

CVSS severity9.8
Critical
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Erik Dubbelboer's phpRedisAdmin 1.16.0 through 1.16.1 allows remote attackers to access Redis via HTTP Digest. The authHttpDigest function in includes/login.inc.php loosely compares the supplied response with an MD5 digest, allowing magic-hash strings treated as numeric zero to compare equal. Exploitation requires HTTP Digest authentication and a crafted response reaching that comparison, after which Redis data can be read, changed, or deleted through the interface.

The record

CVE
CVE-2021-4259
Published
Dec 19, 2022
Updated
Aug 3, 2024
Vendor
Erik Dubbelboer
Product
phpRedisAdmin
Classifications
CWE-597, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 19, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=1.16.0
  2. Affected versionversion=1.16.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Erik Dubbelboer · phpRedisAdminversion=1.16.0; version=1.16.1

Published CVSS scores

5.0VulDBCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
9.8NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-597Use of Wrong Operator in String Comparison
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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