CVE-2026-76205

Executive Summary

CVE-2026-76205 is a SQL injection vulnerability in phpMyFAQ affecting versions prior to 4.1.7. The flaw resides in the glossary create and update endpoints, where the application truncates an escaped string before embedding it in a SQL literal, allowing an authenticated user with glossary permissions to break out of the query context. Successful exploitation permits reading sensitive database information and potentially modifying data, with a CVSS score of 8.1 (High). The vulnerability requires authentication and low-privilege access, making it a significant risk for any public-facing phpMyFAQ instance with glossary functionality enabled.

Technical Analysis

The vulnerability is classified under CWE-89 (SQL Injection) and exists in phpMyFAQ versions prior to 4.1.7. Based on the NVD description, the root cause is an input-handling flaw in the glossary creation and update functionality. The application attempts to sanitize user-supplied input by escaping special characters (likely including the single quote character) before incorporating the value into a SQL statement. However, a truncation operation is performed after the escaping step — this sequence of operations introduces a critical weakness.

The described mechanism: when an attacker supplies a payload containing a trailing backslash (e.g., a string ending in \), the escaping logic converts the closing quote character accordingly, but the subsequent truncation removes the character immediately following the backslash. This leaves the closing quote in a "dangling" state — the SQL parser no longer sees a properly closed string literal. The attacker's input effectively escapes the quote that normally terminates the literal, allowing appended SQL syntax to be interpreted as part of the statement rather than as data.

This is a classic "truncation-after-escaping" SQL injection pattern. The attack surface is the glossary module's create and update endpoints, which accept the glossary entry name and/or definition as input. The vulnerability is only reachable by authenticated users who hold "glossary add or edit permissions" — this implies role-based access control within phpMyFAQ, and the endpoint is accessible over the network. The attacker does not need any special user interaction (UI:N).

Due to insufficient technical detail in the CVE description, specific parameter names, function names, and exact SQL query structures are not available. The precise mechanics of how the truncation occurs (e.g., character limit enforcement, display truncation, or normalization) and which fields are affected (title, definition, language, etc.) are not disclosed. The description does indicate that the escaped string is truncated "before embedding it in a SQL literal," confirming that the truncation is an application-layer operation, not a database-side limitation. The injection point is within a string literal context, given the reference to escaping the "closing quote."

The CVSS vector (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N) indicates a network-accessible flaw requiring low privileges, with no user interaction needed. The impact is limited to confidentiality and integrity (High/High) with no availability impact.

Exploitation Scenarios

The attack chain for CVE-2026-76205 proceeds as follows:

1. Reconnaissance and Target Identification: An attacker first identifies phpMyFAQ installations. This can be done via internet-wide scanning using HTTP title or favicon fingerprinting (e.g., searching for "phpMyFAQ" in page titles or the FAQQUEUE fingerprint). The attacker then determines whether the version is prior to 4.1.7 — potentially probing version endpoints, release notes, or specific HTML comments. Crucially, the attacker must also assess whether an account with glossary permissions exists or can be obtained, as the vulnerability requires an authenticated session with the relevant role.

2. Authentication and Privilege Acquisition: The attacker authenticates to the phpMyFAQ instance with a low-privileged account that has been granted glossary add or edit permissions. In a typical deployment, this could be any registered user if the administrator configured the glossary module to allow self-service contributions, or it may require a specifically provisioned moderator account.

3. Triggering the SQL Injection: At the vulnerability-class level, the attacker submits a crafted payload to the glossary create or update form. The payload includes a dangling backslash — a backslash placed such that after the application's escaping routine runs, the following truncation leaves an unterminated string literal in the generated SQL. For example, a value ending with a backslash would escape the closing quote of the SQL literal, and the truncation step would strip the character designed to restore balance. The attacker then appends malicious SQL syntax after the escaped segment.

   No public PoC is available; the attack chain is inferred from the vulnerability class and CVSS description. The specific character encoding, URL parameter names, and exact query structure are not disclosed in public sources.

4. Post-Exploitation Impact: With the closing quote escaped, the attacker's supplied SQL syntax is interpreted as part of the statement. The CVSS vector indicates High confidentiality and integrity impact — the attacker can read arbitrary data from the database (e.g., user credentials, password hashes, session tokens, configuration data, private FAQ content) and potentially write or modify records (e.g., escalate privileges, alter content, corrupt the glossary data itself). Unauthorized data modification could be used to deface the FAQ, inject client-side scripts into stored content, or tamper with user accounts. The attack specifically targets the database layer, not the web server or OS.

Impact Assessment

Business Impact: phpMyFAQ is a widely deployed open-source FAQ management system. Organizations use it to provide self-service support, host product documentation, and manage internal knowledge bases. A SQL injection in the glossary module affects any site running a version before 4.1.7 where the glossary feature is enabled and accessible to authenticated users.

Affected Systems: All phpMyFAQ instances prior to version 4.1.7 with the glossary module enabled. The vulnerability is only triggerable by authenticated users with glossary add or edit permissions, but in many deployments these permissions are granted to broad user roles. The database backend could be MySQL, MariaDB, or another SQL-compliant RDBMS supported by phpMyFAQ.

Blast Radius: The CVSS subscores are C:H (complete confidentiality compromise of database contents) and I:H (high integrity impact). An attacker who can read the database can extract password hashes, session identifiers, email addresses, and internal corporate information stored in the FAQ. Integrity compromise could allow modification of FAQ content, defacement, or privilege escalation if the application stores roles in the affected database. The attack does not require user interaction, increasing the risk of automated exploitation once a PoC is public.

Exploitation Status: No public PoC, exploit code, or Nuclei template is available. The CVE is not listed on the CISA KEV catalog, and no in-the-wild campaigns have been reported. However, given that the vulnerability class is well-understood and the access requirements are modest (low-privilege authenticated user), the likelihood of weaponization increases once more technical details are disclosed.

Detection Guidance

Sigma Rule

title: phpMyFAQ Glossary SQL Injection Attempt
id: <generated-uuid>
status: experimental
description: Detects SQL injection attempts targeting phpMyFAQ glossary endpoints
logsource:
  category: webserver
  product: apache
  service: access_log
detection:
  selection:
    cs-method:
      - 'POST'
      - 'PUT'
    cs-uri-query|contains:
      - '/glossary'
      - 'glossary'
  keywords:
    - "\\'"
    - "\\\\"
    - "UNION SELECT"
    - "OR 1=1"
    - "SLEEP("
    - "information_schema"
  condition: selection and keywords
  timeframe: 5m
falsepositives:
  - Legitimate glossary edits containing backslash characters in FAQ text
  - URL-encoded content in legitimate administrative actions
level: high
tags:
  - attack.t1190
  - cve.2026-76205

YARA Rule

rule phpMyFAQ_Glossary_SQLi_CVE_2026_76205 {
    meta:
        author = "Valtersit Threat Intel"
        description = "Detects HTTP payloads targeting phpMyFAQ glossary with dangling backslash SQLi patterns"
        cve = "CVE-2026-76205"
        date = "2026-01-01"
        severity = "high"
    strings:
        $s1 = /glossary[^"]*[\x27\x22]/
        $s2 = /\\[\x27\x22][^;]{0,20}(OR|UNION|SELECT|INSERT|UPDATE|DELETE)/i
        $s3 = /%5C%27/
        $s4 = /\\x27/
        $s5 = /information_schema/i
        $s6 = /SLEEP\s*\(/i
    condition:
        uint16(0) == 0x0D0A and any of ($s1*) and (any of ($s2*) or any of ($s3*) or any of ($s4*) or any of ($s5*) or any of ($s6*))
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"ET WEB_SERVER phpMyFAQ Glossary SQL Injection Attempt (CVE-2026-76205)"; flow:established,to_server; content:"glossary"; http_uri; nocase; content:".php"; http_uri; nocase; pcre:"/(\\\\['\"][^;]{0,50}(OR|UNION|SELECT|SLEEP|UPDATE|INSERT))|(%5c%27)/i"; classtype:web-application-attack; sid:2026762051; rev:1;)

Elastic Detection

sequence by source.ip, user.name with maxspan=5m
  [ network where event.type == "start" and destination.port == 80 or destination.port == 443 ]
  [ http where http.request.method in ("POST", "PUT") and
      (http.request.uri contains "glossary") and
      (http.request.body contains "\\'" or
       http.request.body contains "%5c%27" or
       http.request.body contains "UNION SELECT" or
       http.request.body contains "OR 1=1")
  ]

Splunk SPL Query

index=web sourcetype=access_combined
| where like(uri, "%glossary%")
| where method IN ("POST", "PUT")
| eval suspicious_body=if(match(form_data, "\\\\'") OR match(form_data, "%5c%27") OR match(form_data, "UNION SELECT") OR match(form_data, "SLEEP\\("), 1, 0)
| where suspicious_body=1
| table _time, src_ip, method, uri, form_data, status
| sort - _time
| stats count by src_ip, uri

Wazuh OSSEC Rule

<rule id="100005" level="12">
  <decoded>apache-accesslog</decoded>
  <match>glossary</match>
  <regex>(\\)(\x27|\x22)|(UNION SELECT)|(OR 1=1)|(SLEEP)</regex>
  <description>Possible phpMyFAQ SQL injection attempt against glossary endpoint (CVE-2026-76205)</description>
  <group>web_application_attack,sql_injection,cve_2026_76205,</group>
  <mitre>
    <id>T1190</id>
  </mitre>
</rule>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED — no patch evidence from any tracked source.

1. Immediate Mitigations (no official patch available):

   • Disable the glossary module entirely if it is not business-critical. This removes the vulnerable attack surface completely.
   • If the glossary module must remain active, restrict access: revoke glossary add/edit permissions from all non-essential user roles, leaving only trusted administrators with access.
   • Implement a Web Application Firewall (WAF) rule to block requests containing SQL metacharacters or suspicious patterns (backslash-quote sequences, UNION keywords, SLEEP() calls) toward glossary-related URIs.
   • Monitor access logs for unusual POST/PUT requests to the glossary endpoints, especially those containing backslash or quote characters.
   • Enforce strong password policies and enable MFA for all accounts — a compromised low-privilege account is the precondition for exploitation.

2. Patch/Upgrade Steps:

   • Monitor phpMyFAQ release channels for version 4.1.7 or later. The vendor has acknowledged the fix in 4.1.7, but as of this report, no patch artifact or release candidate is available from any tracked source.
   • Once the patched version is released, upgrade immediately. Test the upgrade in a staging environment first to validate compatibility with existing FAQ data and plugins.
   • If you are running a distribution-packaged version of phpMyFAQ, check your OS vendor's repository for a backported fix — though no evidence of such backport exists at this time.

3. Long-Term Hardening:

   • Ensure the phpMyFAQ database user operates with least-privilege: no file read/write, limited to necessary tables. Verify the application's DB credentials do not have superuser or global privileges.
   • Implement database-level audit logging for sensitive operations (e.g., SELECT on user tables) to detect post-exploitation data exfiltration.
   • Keep phpMyFAQ and its PHP runtime patched; review the application's secure coding guidelines and consider contributing input-validation improvements upstream.
   • Conduct periodic security reviews of phpMyFAQ source code, focusing on all database-interaction code paths, not just glossary endpoints. The "truncation-after-escaping" pattern may exist in other modules.
   • Use parameterized queries (prepared statements) as the standard defense — this is the definitive fix for this vulnerability class.

References

1. NVD Entry for CVE-2026-76205: https://nvd.nist.gov/vuln/detail/CVE-2026-76205
2. phpMyFAQ Official Website and Release Notes: https://www.phpmyfaq.de/
3. CWE-89 (SQL Injection) — MITRE: https://cwe.mitre.org/data/definitions/89.html
4. ATT&CK Technique T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/

No CISA KEV listing exists for this CVE. No known threat actor campaigns or exploit-in-the-wild evidence were identified at the time of writing.