CVE-2026-34959: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-fh9x-8h7v-rwhv
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CVSS 4.7
CWE-20
Published
Advisory Summary

CVE-2026-34959 is a MODERATE (CVSS 4.7) security vulnerability vulnerability (CWE-20: Improper Input Validation) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-34959 at a Glance

CVE Identifier CVE-2026-34959
GHSA Identifier GHSA-fh9x-8h7v-rwhv
Severity MODERATE
CVSS v3.1 Base Score 4.7
CWE Classification CWE-20: Improper Input Validation
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 4.7

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-34959

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-34959, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Adminer 4.6.0 before 5.5.0 prepends the client-supplied X-Forwarded-Prefix header to $_SERVER["REQUEST_URI"] with no trusted-proxy check and no validation of the prefix value. An attacker can supply an absolute URL (e.g. X-Forwarded-Prefix: https://evil.example) that flows into Location redirect headers, the Set-Cookie path attribute, and self-referential links. This enables an authenticated open redirect after state-changing POSTs, unauthenticated control of the session cookie path attribute, and poisoning of self-referential links; CR/LF cannot be injected, so header splitting/XSS is not possible.

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vrana/adminer/security/advisories/GHSA-8478-xrj3-h9c2
NVD — CVE-2026-34959 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34959
www.vulncheck.com/advisories/adminer-... WEB
https://www.vulncheck.com/advisories/adminer-before-open-redirect-via-x-forwarded-prefix

Frequently Asked Questions

What is CVE-2026-34959?
CVE-2026-34959 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-20: Improper Input Validation.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-34959?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-34959?
CVE-2026-34959 has a CVSS v3.1 base score of 4.7 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N.
What CWE is associated with CVE-2026-34959?
CVE-2026-34959 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check Maven dependencies for CVE-2026-34959?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fh9x-8h7v-rwhv",
  "modified" : "2026-08-25T03:32:08Z",
  "published" : "2026-08-25T03:32:08Z",
  "aliases" : [ "CVE-2026-34959" ],
  "details" : "Adminer 4.6.0 before 5.5.0 prepends the client-supplied X-Forwarded-Prefix header to $_SERVER[\"REQUEST_URI\"] with no trusted-proxy check and no validation of the prefix value. An attacker can supply an absolute URL (e.g. X-Forwarded-Prefix: https://evil.example) that flows into Location redirect headers, the Set-Cookie path attribute, and self-referential links. This enables an authenticated open redirect after state-changing POSTs, unauthenticated control of the session cookie path attribute, and poisoning of self-referential links; CR/LF cannot be injected, so header splitting/XSS is not possible.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vrana/adminer/security/advisories/GHSA-8478-xrj3-h9c2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34959"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/adminer-before-open-redirect-via-x-forwarded-prefix"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-25T02:16:40Z"
  }
}