CVE-2026-78625

Executive Summary

CVE-2026-78625 describes an unauthenticated-equivalent (post-authentication) code injection vulnerability in the Okta Access Gateway, a reverse proxy and authentication component used to protect legacy on-premises web applications. The root cause is a failure to sanitize dashboard label values before they are written into generated PHP configuration files, which are subsequently parsed during authentication requests. A malicious actor with administrative access to the dashboard can inject arbitrary PHP payloads into configuration values that execute with web server process privileges on every authentication request. At time of writing, no vendor patch exists, no public exploit code has been released, and the vulnerability has not been added to CISA's Known Exploited Vulnerabilities catalog.

Technical Analysis

The underlying vulnerability class is CWE-94 — Improper Control of Generation of Code ('Code Injection'). The Okta Access Gateway appears to maintain a control plane where administrators can configure operational parameters, including human-readable labels associated with dashboard panels, alerts, or monitored resources. These label values are persisted to disk as part of generated PHP configuration files during the configuration-save operation.

The NVD description states that label values are written into a "generated PHP configuration file" without sanitization. The generated file is then "automatically included during authentication requests." The term "included" strongly implies the use of a PHP server-side include (include or require construct, although specific function names are not disclosed). When PHP includes a file, all content outside <?php ... ?> delimiters is emitted as literal output, and any content within PHP opening tags is interpreted and executed at the language level.

The attack mechanism is therefore as follows:

1. The application receives a label value, e.g., a string typed into a dashboard configuration field.
2. That string is concatenated into a PHP source file during configuration generation, with no escaping, encoding, or validation applied to the user-controlled component.
3. Because the unsanitized string stays in-band with the PHP source code, an attacker who controls the label value also controls a portion of the eventual PHP program.
4. When authentication requests hit the gateway, the PHP runtime loads the configuration file as part of its session or authentication bootstrap, triggering execution of any embedded PHP directives.

The attack is classified as local (AV:L) with high privileges required (PR:H) in the CVSS vector, indicating that the practical exploitation path requires an authenticated administrative user — someone who can already reach the dashboard and save configuration changes. However, the privilege requirements may be misleading if the dashboard is reachable from a lower-privileged portal user or if cross-site request forgery exists on the label submission endpoint; no such data is available in the provided description.

The CVSS vector additionally indicates "no user interaction" (UI:N), meaning the execution does not require a separate victim to trigger the payload beyond the standard authentication flow that naturally includes the generated file. The scope is unchanged (S:U) because the injected code executes within the same trust boundary of the web server process, though the impact rating is High for confidentiality, integrity, and availability (C:H/I:H/A:H), reflecting that PHP code execution under the web server account typically results in full file system access to application data, configuration secrets, and credential material held by the gateway.

Insufficient technical detail is available regarding which specific configuration endpoint accepts label input, whether the environment is self-hosted or Okta cloud-managed, or which PHP version/SAPI is used. The description likewise does not disclose the exact file path where generated PHP files are stored, nor whether the include happens for every request or only on authentication initiation. These details are required for a signature-level detection rule and should be requested from the CNA if access to the underlying advisory is available.

Exploitation Scenarios

The following attack chain is inferred strictly from the vulnerability class and the provided NVD description. No public PoC exists, so the chain is generic for PHP code injection through unsanitized configuration directives.

Step 1 — Reconnaissance and target identification. An attacker with administrative credentials (or who has gained them through phishing, credential stuffing, or lateral movement) locates the Okta Access Gateway administrative console. The console is usually bound to an internal network or a management VLAN; exposure to the Internet is possible but atypical. The attacker enumerates the dashboard configuration menus to identify fields labeled as "labels" — for example, custom names for dashboard panels, authentication policies, or monitored backend applications. The goal is to find any input field whose value will be persisted into a file with a .php extension or included at runtime.

Step 2 — Triggering the vulnerability. The attacker chooses a label field likely to be written to the generated configuration. In a PHP code injection scenario of this class (CWE-94), the attacker submits a value that terminates the literal mode of the PHP file and opens a PHP code block. A typical payload at the vulnerability-class level is: </anything><?php <malicious PHP statements> ?> — the closing angle bracket terminates the previous context and <?php opens a new code block. Because the application does not sanitize the value, the injected PHP opening tag is written verbatim into the configuration file.

Step 3 — Payload and execution. Once the configuration is saved and regenerated, the attacker triggers any authentication request through the gateway (e.g., browsing to any protected URL that forces the login flow). The PHP runtime automatically includes the poisoned configuration file, executing the injected statements with the privileges of the web server user (commonly www-data, apache, or nginx). At the vulnerability-class level, a minimal payload could attempt to write a web shell (file_put_contents(...)), read sensitive files (file_get_contents(...)), or execute system commands (via system() or similar). The injected code runs on every subsequent authentication request until the configuration file is regenerated or the label value is reverted.

Step 4 — Post-exploitation impact. With arbitrary PHP execution under the web server account, the attacker can:

• Read configuration files containing credentials or cryptographic keys used by the gateway to decrypt sessions or communicate with backend identity providers.
• Modify backend application routing rules to redirect authenticated sessions to attacker-controlled infrastructure.
• Install a persistent backdoor within the web root or via a cron entry outside the web root.
• Pivot laterally to internal resources if the web server account has broader access (e.g., via mounted service accounts or shared storage).
• Escalate privileges if the web server process runs with excessive privileges or if the host OS kernel is unpatched.

Impact Assessment

The CVSS base score of 6.7 (High) reflects the substantial privileges required for exploitation (PR:H) but recognizes the full impact on confidentiality, integrity, and availability once those privileges are obtained. From a risk-management perspective, the vulnerability is most concerning in environments that already face administrative account compromise — an attacker who obtains dashboard access via stolen credentials can achieve immediate remote code execution without needing to chain a second vulnerability.

Business impact is concentrated in the authentication layer. The Okta Access Gateway functions as a choke point between users and one or more legacy applications. Code execution at this layer allows an attacker to hijack the entire authentication flow, intercept credentials transmitted during login, and manipulate session tokens. For organizations using the gateway to protect compliance-scoped systems (PCI DSS, HIPAA, SOX), a full compromise of the authentication boundary may constitute a reportable breach event that triggers notification obligations.

Attack surface is broader than the gateway alone: the web server process typically also runs the administrative UI. Compromise of the web server process grants access to whatever files and sockets that process can reach, which commonly includes the local session store, cached identity provider metadata, and log files containing user identifiers. Lateral movement from this position is realistic but not guaranteed.

Availability impact is straightforward — injected code could delete configuration files, corrupt the generated PHP directives, or cause the gateway to crash — resulting in denial of service for all users of protected applications behind the gateway.

Detection Guidance

Sigma Rule

title: Okta Access Gateway PHP Code Injection via Dashboard Label
id: e0c6a4f1-6d3a-4b7e-8a5c-2f9b1c4e7d3a
status: experimental
description: >
  Detects suspicious modifications to dashboard label fields that contain PHP
  opening tags or code-execution primitives, indicative of CVE-2026-78625 exploitation.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-78625
author: Valtersit Threat Intelligence
date: 2026/01/01
logsource:
  category: application
  product: okta_access_gateway
detection:
  selection_php_tags:
    - label_value: '*<?php*'
    - label_value: '*<?=*'
    - label_value: '*?>*'
  selection_code_exec:
    - label_value: '*system(*'
    - label_value: '*exec(*'
    - label_value: '*passthru(*'
    - label_value: '*shell_exec(*'
  selection_backticks:
    - label_value: '*`*'
  condition: selection_php_tags or selection_code_exec or selection_backticks
  timeframe: 5m
falsepositives:
  - Legitimate administrators may include mathematical expressions containing <? or > characters in labels; validate before blocking.
level: high

YARA Rule

rule Okta_Access_Gateway_PHP_Code_Injection_CVE_2026_78625
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects PHP code injection payloads written into Okta Access Gateway configuration label values (CVE-2026-78625)"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-78625"
        cve = "CVE-2026-78625"
        score = 60

    strings:
        $php_open = "<?php"
        $php_short = "<?="
        $cmd_system = "system("
        $cmd_exec = "exec("
        $cmd_shell = "shell_exec("
        $cmd_passthru = "passthru("
        $file_write = "file_put_contents("
        $file_read = "file_get_contents("
        $backtick = "`"

    condition:
        any of ($php_open, $php_short) and
        (any of ($cmd_system, $cmd_exec, $cmd_shell, $cmd_passthru) or
         any of ($file_write, $file_read) or
         $backtick)
}

Suricata IDS Rule

Given that the exploitation occurs through an administrative HTTP interface (HTTPS typically), most realistic detection will occur at the HTTP layer. The following rule inspects HTTP request bodies (POST data) for PHP payloads delivered to the dashboard configuration endpoint. Note: specific URI paths are not disclosed in the NVD description; the rule therefore matches on combined HTTP attributes.

alert http any any -> $HOME_NET any (msg:"CVE-2026-78625 - Okta Access Gateway PHP injection payload in HTTP request body"; flow:established,to_server; content:"POST"; http_method; content:".php"; http_uri; nocase; pcre:"/<\?(?:php|=)/Ui"; content:"system\s*\("; nocase; pcre:"/<\?(?:php|=)/Ui"; sid:20267862501; rev:1; metadata:attack_target_web_server, cve_2026_78625, tag_code_injection;)

Documentation note for SOC analysts: The Suricata rule above can only fire on plaintext inspection; if the admin console enforces TLS (expected), additional decryption (suricata-ja3 / TLS proxy) or host-level detection is required.

Elastic Detection

EQL query for host-level detection of suspicious PHP file writes or altered configuration files:

sequence by host.name with maxspan=5m
  [ file where event.action in ("write", "modify") and
      file.name endswith ".php" and
      file.path like "*okta*" and
      process.name not like "*php-fpm*" ]
  [ file where event.action in ("write", "modify") and
      file.name endswith ".php" and
      process.name not like "*php-fpm*" ]

An additional detection can inspect file content for PHP payloads:

any where process.name == "php" and
  process.args == "include" and
  process.command_line like "*/tmp/*" or
  process.command_line like "*config*"

Splunk SPL Query

Detecting exploitation of CVE-2026-78625 requires brokering host and application logs. The following SPL indexes web proxy logs, authentication service logs, and configuration file integrity events:

index=okta OR index=webproxy OR sourcetype=okta:accessgateway
| search label_value IN (*<?php*, *<?=*, *system(*, *exec(*)
| eval malicious = if(match(label_value, "<\?(php|=)|(system|exec|shell_exec|passthru)\s*\("), 1, 0)
| where malicious == 1
| table _time, src_ip, user, dashboard_id, label_name, label_value
| sort - _time

Alternative correlation looking for recent configuration timestamp followed by PHP execution events from the web server process:

index=okta sourcetype=config_change
| table _time host user action component
| append [ search index=os sourcetype=syslog process=php*
    | where pid IN (process_started)
    | iplocation src_ip
    | table _time host user process command ]
| eventstats earliest(_time) as config_save_time by host
| eval config_change = if(action=="save", "yes", "no")
| where config_change=="yes" AND _time >= config_save_time AND _time < relative_time(now(), "+10m")

Wazuh OSSEC Rule

The Wazuh rule below looks for PHP process executions shortly after a configuration write on the Okta gateway host. Adjust file paths to your environment.

<group name="okta_access_gateway,">
  <rule id="100251" level="12">
    <decoded_as>json</decoded_as>
    <field name="event.module">auditd</field>
    <field name="auditd.type">SYSCALL</field>
    <field name="auditd.syscall">execve</field>
    <field name="auditd.comm">php</field>
    <match>okta</match>
    <description>CVE-2026-78625: PHP process execution on Okta Access Gateway host shortly after config write</description>
    <group>code_injection,</group>
    <mitre>
      <id>T1505.003</id>
    </mitre>
  </rule>

  <rule id="100252" level="14">
    <if_sid>100251</if_sid>
    <field name="auditd.exe">/usr/bin/php</field>
    <description>CVE-2026-78625: Confirm PHP execution from system php binary</description>
    <group>code_injection_confirmed,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch status: UNPATCHED (confidence 0/4). No official vendor fix has been identified as of the latest data collection. Organizations should assume all current versions of the Okta Access Gateway are affected.

Immediate mitigations (no patch available):

1. Restrict administrative console access. Remove the dashboard from any internet-facing interface; require VPN/IP-allowlist access to the management console; enable multi-factor authentication on all admin accounts. The CVSS vector PR:H means an attacker must reach dashboard functionality with valid credentials — limiting reachability substantially reduces exposure.
2. Audit all dashboard label values. Review current label fields for any content containing <?php, <?=, backtick characters, or references to system(), exec(), or other command-execution functions. Revert any suspicious values to plain alphanumeric strings.
3. Deploy a web application firewall (WAF) in front of the admin console (if it must be exposed) with rules rejecting POST bodies containing <?php or <?= patterns.
4. Enhance audit logging on the configuration save endpoint, capturing the user identity, source IP, and full label content of any modification. Retain these logs for a minimum of 90 days per typical compliance frameworks.

Patch/Upgrade steps:

• Monitor Okta's official security advisory page and the CVE entry for updates. Subscribe to the Okta Trust bulletin list.
• When a patch is released, apply it in a staged rollout: first on a non-production instance and verify configuration regeneration does not suffer data loss; then to production during a maintenance window with a rollback path.
• If Okta provides a configuration-scanner utility, run it before patching to identify existing injected payloads.

Long-term hardening:

• Transition away from dashboard labels that feed any generated content; use immutable identifiers when available.
• If self-hosting the gateway, run the web server process under a least-privilege service account with write access restricted to only necessary directories. Consider a read-only bind mount for the configuration directory after initial generation.
• Implement file integrity monitoring (e.g., Wazuh with FIM module, OSSEC, or Tripwire) on generated PHP configuration file paths.
• Where possible, replace the Okta Access Gateway with a modern reverse proxy that maintains configuration in structured data formats (YAML/JSON) rather than server-parsed source files — reducing the risk of this vulnerability class entirely.

References

1. NVD entry for CVE-2026-78625 — National Institute of Standards and Technology: https://nvd.nist.gov/vuln/detail/CVE-2026-78625
2. Okta Trust & Security Advisories page (monitor for vendor advisory): https://trust.okta.com/security-advisories
3. MITRE ATT&CK Technique T1505.003 — Server Software Component: Web Shell: https://attack.mitre.org/techniques/T1505/003/
4. CWE-94 — Improper Control of Generation of Code ('Code Injection'): https://cwe.mitre.org/data/definitions/94.html
5. CISA Known Exploited Vulnerabilities Catalog (CVE not listed as of writing): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No public exploit code has been released. No evidence suggests exploitation in the wild as of this report. The vulnerability is not listed in CISA KEV, Epic SSVC, or any other tracked threat-intelligence feed reviewed during this analysis.