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Tainacan CVE-2026-94676

| EUVDEUVD-2026-96323 HIGH
Deserialization of Untrusted Data (CWE-502)
2026-10-10 audit@patchstack.com GHSA-g3x7-hv56-2x6h
7.2
CVSS 3.1 · Vendor: patchstack
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain high-privilege authenticated access
  2. Delivery
    Submit crafted serialized PHP object
  3. Exploit
    Trigger unsafe unserialize() in plugin
  4. Execution
    Instantiate malicious gadget chain
  5. Impact
    Execute arbitrary code / full compromise

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V1 - Encoding and Sanitization Safe deserialization, type allowlists
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires an authenticated session with high privileges (CVSS PR:H - effectively a WordPress administrator or equivalent role that can reach the plugin input which is deserialized), against a site running the Tainacan plugin version 1.3.0 or earlier. The core precondition is that attacker-controlled data reaches the plugin's unserialize() path; successful object injection additionally depends on a usable POP/gadget chain being present in the loaded codebase (plugin, WordPress core, or other active plugins). Primary limiting factors: the high-privilege authentication requirement sharply narrows the attacker population, and the plugin's niche deployment (digital repository/collection management) limits the attack surface; no user interaction is required (UI:N) and the vector is network-based (AV:N).

Impact

This is a CWE-502 PHP Object Injection flaw in the Tainacan WordPress plugin (affected through 1.3.0), with a vendor/NVD-sourced CVSS 3.1 score of 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H). The signals are internally consistent but point to a moderate, not emergency, real-world priority. The vector is network-reachable with low attack complexity and no user interaction, and the triple-High impact (C/I/A) reflects the typical RCE/full-compromise potential of object injection - however, PR:H means the attacker must already hold high privileges (effectively an administrator or equivalent authenticated role), which is the dominant risk-limiting factor. No EPSS score, CISA KEV listing, or public POC is present in the provided data, so there is no public exploit identified at time of analysis and no evidence of active exploitation. The combination (high impact but high-privilege precondition, no exploitation signals) places this as a worthwhile patch target rather than a drop-everything issue. Note a gap: the input provides no EPSS/KEV/POC data at all - their absence is not evidence of low risk, only of missing enrichment, so monitoring is advised.

Exploit ScenarioDerived

An attacker who already holds a high-privilege (administrator-level) account on a WordPress site running Tainacan ≤1.3.0 submits a crafted serialized PHP payload to an input that the plugin deserializes without validation. The unserialize operation instantiates attacker-controlled objects, triggering a gadget chain that can lead to arbitrary file operations, SQL injection, or remote code execution in the site context. No public exploit code is identified at time of analysis, and the attack requires no victim user interaction.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 10, 2026

PHP object injection in the Tainacan WordPress plugin (all versions through 1.3.0) allows an authenticated high-privilege user - per the assessed CVSS vector (PR:H), effectively a WordPress administrator or an equivalent role able to reach the vulnerable input - to pass attacker-controlled serialized data into the plugin's deserialization path and potentially instantiate arbitrary PHP objects. Rated CVSS 3.1 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H), the flaw carries high confidentiality and integrity impact but is sharply constrained by the privileged authentication prerequisite and the plugin's niche use as a digital repository/collection management tool for WordPress. No public exploit code or confirmed active exploitation was identified at time of analysis, and object injection would additionally require a usable POP/gadget chain in the loaded codebase to convert into concrete code execution or file manipulation.

RemediationAI

No exact fixed version is stated in the provided intelligence, so the first step is to check the vendor's Patchstack advisory (https://patchstack.com/database/wordpress/plugin/tainacan/vulnerability/wordpress-tainacan-plugin-1-3-0-php-object-injection-vulnerability?_s_id=cve) and the Tainacan project's release channel for an update beyond 1.3.0 - the safe action is to upgrade the Tainacan plugin to the earliest release that the vendor confirms as patched, and to treat 1.3.0 and earlier as vulnerable until that confirmation is available. Because the assessed vector requires high privileges (PR:H), the most effective compensating control is to minimize and audit accounts holding administrator or equivalent capabilities that can reach the plugin's deserialization input, removing standing admin rights from users who do not need them and enforcing strong authentication on the remaining ones; the trade-off is added administrative friction and possible operational disruption for legitimate site managers. On sites where Tainacan is not actively used, deactivating and deleting the plugin removes the exposed code path entirely at the cost of losing repository functionality. Because successful object injection depends on a usable gadget chain, keeping WordPress core, themes, and all other plugins fully patched reduces the pool of exploitable classes, though it does not eliminate the underlying unserialize() flaw in Tainacan itself. A web application firewall or request-inspection rule that flags serialized-object payloads (for example 'O:' patterns) in requests to Tainacan endpoints can add detection coverage, but such signatures are prone to false positives and bypass, so they should be treated as monitoring rather than a fix. Finally, log and alert on administrator-level activity touching Tainacan functionality to detect attempted exploitation, since no vendor patch identifier is confirmed in the available data.

Affected VersionsENISA

Tainacan 0 ≤1.3.0

Affected Packages

euvd tainacan no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-502 (Deserialization of Untrusted Data): the Tainacan plugin for WordPress feeds data it does not adequately validate into PHP's unserialize()/deserialization machinery. In PHP, deserializing untrusted input lets an attacker control which classes are instantiated and which magic methods (__wakeup, __destruct, __toString, etc.) fire; chaining those methods across classes already loaded in the request - the plugin itself, WordPress core, the active theme, or other installed plugins - produces a 'POP chain' that can escalate a simple object instantiation into file writes, data exfiltration, or code execution. Exploitation is therefore context-dependent: the vulnerable plugin entry point must be reachable by the attacker (CVSS PR:H indicates a high-privileged authenticated session is required, consistent with an administrative capability exposed by the plugin rather than an anonymous-facing endpoint), and a viable gadget chain must exist in the deployed environment. The NVD/patchstack reference is a WordPress-plugin advisory (patchstack database entry for the Tainacan 1.3.0 PHP object injection), and no CPE strings were supplied in the source data, so affected-product identification relies on the advisory's WordPress plugin slug rather than a formal CPE.

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Severity by source

Vendor (patchstack) PRIMARY 7.2 HIGH
AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.2 HIGH

Network-reachable with low complexity and no interaction, but object injection here requires a high-privilege authenticated account (PR:H); gadget-driven deserialization yields full C/I/A impact within the site scope.

3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (patchstack).

CVSS VectorVendor: patchstack

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Deserialization of Untrusted Data vulnerability in Tainacan Community Tainacan tainacan allows Object Injection.This issue affects Tainacan: from n/a through 1.3.0.

Executive ViewAI

Why It Matters

The Tainacan WordPress plugin, used for digital repository management, contains a PHP object injection vulnerability in all versions through 1.3.0 that could allow an authenticated administrator-level user to manipulate data or potentially execute code. While exploitation requires high privileges and no public exploit exists, the flaw carries high confidentiality and integrity impact, so organizations relying on this plugin should prioritize mitigating the risk of insider threats or compromised admin accounts.

Business Impact: Medium
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict administrator access to only trusted personnel, enforce least privilege, deploy WAF rules to detect and block serialized object injection attempts, and disable the Tainacan plugin if it is not business-critical.

Threat Intelligence Overview

EPSS Score
0.3%
Top 79% exploitable
Prevalence
Low
niche WordPress digital-collections plugin, mainly GLAM/museum sites
Social Media
1
Sightings
Data Quality
7 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Medium
Technical Impact
Total

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.

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