CVE-2026-34959Public exploitNetwork attack vectorHinoki check available

Open redirect via unvalidated X-Forwarded-Prefix

Published Aug 25, 2026 · Updated Aug 26, 2026

Improper input validation in Adminer 4.6.0 through 5.4.4 allows remote attackers to poison redirects and cookie paths via an HTTP header. The bootstrap code prepends an unvalidated X-Forwarded-Prefix value to REQUEST_URI without checking for a trusted proxy, and the resulting absolute URL reaches redirect, cookie-path, and self-link sinks. Redirecting an operator requires an authenticated state-changing POST and user interaction, while cookie-path and self-link manipulation are reachable before authentication; CR/LF injection is rejected.

CVSS severity5.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Improper input validation in Adminer 4.6.0 through 5.4.4 allows remote attackers to poison redirects and cookie paths via an HTTP header. The bootstrap code prepends an unvalidated X-Forwarded-Prefix value to REQUEST_URI without checking for a trusted proxy, and the resulting absolute URL reaches redirect, cookie-path, and self-link sinks. Redirecting an operator requires an authenticated state-changing POST and user interaction, while cookie-path and self-link manipulation are reachable before authentication; CR/LF injection is rejected.

The record

CVE
CVE-2026-34959
Published
Aug 25, 2026
Updated
Aug 26, 2026
Vendor
Adminer
Product
Adminer
Classifications
CWE-601, CWE-20, CWE-441
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 2026Record 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 <5.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Adminer · Adminerversion=0 <5.5.0

Published CVSS scores

5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
4.7VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CWE-20Improper Input Validation
CWE-441Unintended Proxy or Intermediary ('Confused Deputy')

Public exploit references

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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