CVE-2026-93945

Executive Summary

CVE-2026-93945 is a critical deserialization of untrusted data vulnerability (CWE-502) in the Axiomthemes Balance WordPress theme, affecting versions up to and including 1.12.0. The flaw permits object injection through unsafe deserialization of attacker-controlled input, and with a CVSS v3.1 base score of 9.8, exploitation requires no authentication, no user interaction, and no special privileges. Successful exploitation can lead to full remote code execution, compromising the confidentiality, integrity, and availability of the host web server and any data reachable by it.

Technical Analysis

The vulnerability resides in the Axiomthemes Balance theme, a commercially distributed WordPress theme. The assigned CWE is CWE-502 — Deserialization of Untrusted Data — and the CNA-provided description states that the flaw "allows Object Injection" via the deserialization of untrusted data. This class of defect occurs when an application passes attacker-supplied data into a deserialization routine (in the PHP ecosystem, typically unserialize()) without sufficient validation, type constraints, or an allowed-class whitelist.

When untrusted serialized input is deserialized, the attacker controls both the declared object type and its property values. If the codebase (or the broader WordPress/plugin ecosystem loaded on the same host) contains classes that implement magic methods such as __wakeup(), __destruct(), or __toString(), the attacker can craft a serialized payload that instantiates one of those classes and drives it through a "POP chain" (property-oriented programming) toward a dangerous side effect. Depending on available gadget classes, this can culminate in arbitrary file operations, inclusion of attacker-controlled content, or direct code execution.

The attack surface is network-exposed: the theme is part of a WordPress installation that is reachable over HTTP(S). CVSS reflects AV:N (network) with AC:L (low complexity), indicating the injection point is reachable remotely and is not gated behind race conditions or unusual preconditions. PR:N and UI:N confirm that no authentication or victim interaction is required, which is consistent with an unauthenticated request reaching an entry point that deserializes a user-supplied value. Scope is Unchanged (S:U), meaning the impact is confined to the security authority of the vulnerable component, though confidentiality, integrity, and availability impacts are all rated High (C:H/I:H/A:H).

The exact vulnerable function, class, parameter name, or request endpoint is not disclosed in the NVD description or CNA title. In accordance with the source data, no specific function names, file paths, or parameter identifiers are asserted here; the mechanism is described strictly at the vulnerability-class level. The authoritative fact set available is: deserialization of untrusted data, object injection, network-reachable, unauthenticated, affecting Balance through version 1.12.0.

Exploitation Scenarios

No public proof-of-concept, Nuclei template, or exploit code is available for CVE-2026-93945. The attack chain below is therefore inferred from the vulnerability class (PHP object injection via unsafe deserialization) and the CVSS characteristics, not from a published exploit.

1. Reconnaissance and target identification. An adversary enumerates internet-facing WordPress sites and fingerprints the active theme. Balance is identifiable from common theme asset paths (e.g., wp-content/themes/balance/) and page markup. Public search engines and Shodan-style fingerprinting can scale this enumeration to identify candidate installations running Balance at or below version 1.12.0.

2. Triggering the flaw. The attacker identifies an input path that reaches the theme's deserialization logic and delivers a serialized string. Because the vulnerability class is object injection, the input would be a serialized PHP object crafted to reference a class available in the loaded codebase whose magic methods perform security-relevant actions. The precise entry point (which request parameter or endpoint carries the serialized data) is not specified in the available advisory data and would require source review or dynamic testing to confirm.

3. Payload and execution. Using a POP chain assembled from available gadget classes, the attacker steers deserialization side effects toward a useful primitive. Classic deserialization gadget outcomes include arbitrary file write, file deletion, or command execution. If a suitable chain exists in the theme or the wider PHP environment, the result is code execution in the context of the web server process. Absent a confirmed chain, the achievable primitive remains object injection with consequences dependent on the locally available classes.

4. Post-exploitation impact. Given C:H/I:H/A:H, a successful exploit can expose sensitive data (database credentials in wp-config.php, user records, session material), modify site content or inject persistent malicious code, and disrupt availability. Compromise of a WordPress host commonly enables web-shell deployment, lateral movement to adjacent services, and the site being repurposed for malware distribution or SEO poisoning.

Impact Assessment

The CVSS v3.1 base score of 9.8 (Critical) derives from AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. The unauthenticated, network-reachable, low-complexity profile means exploitation is attractive to mass-scanning botnets and opportunistic actors rather than requiring targeted effort. Blast radius centers on the WordPress installation and the underlying host: all confidentiality, integrity, and availability objectives for the vulnerable component are rated High. Because scope is Unchanged, the scoring model treats impact as bounded to the vulnerable component's authority — but in practice a WordPress host compromise frequently exposes the database, other virtual hosts on shared infrastructure, and stored credentials. Sites running Balance versions up to and including 1.12.0 are affected. EPSS has not yet been scored by FIRST.org, so no probabilistic exploitation estimate is asserted here; CISA KEV status is NO, indicating no confirmed in-the-wild exploitation at the time of this report.

Detection Guidance

Sigma Rule

title: Potential PHP Object Injection via Unsafe Deserialization (CVE-2026-93945)
id: 7c9a1e42-4b6d-4f1a-9c2e-2f0d8a5b6e11
status: experimental
description: Detects request payloads containing PHP serialized object markers, consistent with object injection against the Axiomthemes Balance theme.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-93945
author: valtersit.com
logsource:
  category: webserver
detection:
  selection_object:
    cs-uri-query|contains:
      - 'O:%3A'
      - 'O:'
  selection_props:
    cs-uri-query|contains:
      - '__wakeup'
      - '__destruct'
      - '__toString'
  condition: selection_object and selection_props
falsepositives:
  - Legitimate serialized data passed by trusted applications
level: high

YARA Rule

rule CVE_2026_93945_PHP_Object_Injection
{
    meta:
        description = "Detects PHP serialized object payloads indicative of object injection (CVE-2026-93945)"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-93945"
        author = "valtersit.com"
        date = "2026-01-01"
        severity = "critical"

    strings:
        $php_serial_obj = /O:[0-9]{1,4}:"[A-Za-z0-9_\\]{1,128}"/
        $magic_wakeup  = "__wakeup"
        $magic_destruct = "__destruct"
        $magic_tostring = "__toString"
        $serialized_prop = /s:[0-9]{1,4}:"[^"]{0,64}";/

    condition:
        $php_serial_obj and 1 of ($magic_*)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-93945 Potential PHP Object Injection - Balance Theme"; flow:established,to_server; http.uri; content:"O:"; pcre:"/O:\d+:\x22[A-Za-z0-9_\\\\]+\x22/"; content:"__wakeup"; http.uri; nocase; reference:cve,2026-93945; classtype:web-application-attack; sid:202693945; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=5s
  [http where http.request.method in ("GET","POST") and wildcard(http.request.uri.query, "*O:*")]
  [http where wildcard(http.request.uri.query, "*__wakeup*") or wildcard(http.request.uri.query, "*__destruct*")]

Splunk SPL Query

index=web sourcetype=access_combined
| eval uri=coalesce(uri, url)
| where match(uri, "O:\d+:\"[A-Za-z0-9_\\\\]+\"") AND (like(uri, "%__wakeup%") OR like(uri, "%__destruct%") OR like(uri, "%__toString%"))
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri, status
| where count >= 1
| sort - count

Wazuh OSSEC Rule

<group name="web,attack,cve_2026_93945,">
  <rule id="2026939" level="12">
    <if_sid>31100,31101,31108</if_sid>
    <regex>O:\d+:"[A-Za-z0-9_\\]+"</regex>
    <description>Possible PHP object injection attempt (CVE-2026-93945, Axiomthemes Balance theme)</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_93945,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix and no workaround are available in the provided data.

1. Immediate mitigations. Because the flaw is an unauthenticated network-reachable deserialization issue, treat the theme as compromised-capable input handling. Restrict access to the affected site with an upstream WAF or reverse proxy ruled to block requests carrying serialized object markers (O:<n>:"...") in parameters. Deploy virtual patching at the edge where feasible. Consider temporarily disabling the Balance theme if it is not business-critical. Harden the PHP environment: disable dangerous magic-method gadget classes where possible, and apply a deserialization allowlist via a hardening mu-plugin or non-platform unserialize_callback configuration. Keep the host's PHP version current.

2. Patch/upgrade steps. No vendor patch is currently referenced. Monitor Axiomthemes' official distribution channel and the WordPress theme update mechanism for a fixed release addressing CVE-2026-93945. When a patched version is published, upgrade immediately via the WordPress admin or the official vendor source. Until then, do not rely on version-pinning; there is no safe version above 1.12.0 per current data.

3. Long-term hardening. Apply least-privilege to the web server process (restrict filesystem write access, limit PHP execution to needed paths). Maintain an inventory of installed themes and plugins with version tracking so affected versions are detectable at scale. Enforce deserialization safe-coding standards (type restrictions, allowed-class whitelists) in any custom code. Keep WAF signatures, EDR, and web logs monitored for deserialization-based attack patterns. Run regular integrity checks over theme and plugin files to detect injected webshells.

References

• NVD — CVE-2026-93945: https://nvd.nist.gov/vuln/detail/CVE-2026-93945
• CWE-502 — Deserialization of Untrusted Data: https://cwe.mitre.org/data/definitions/502.html
• CVSS v3.1 Specification: https://www.first.org/cvss/v3.1/specification-document
• CISA Known Exploited Vulnerabilities Catalog (no entry for CVE-2026-93945 as of this report): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Axiomthemes official distribution channel — monitor for updated Balance theme release.

No public PoC, Nuclei template, or exploit code was available at the time of writing. No threat actor campaign or exploit-in-the-wild evidence is associated with CVE-2026-93945 in the provided intelligence, and CISA KEV status is NO.