External risk intelligence

openssl_encrypt Bypass Schema Validation Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-74875

The vulnerability exists in a library function (openssl_encrypt) used for data processing. While it processes data that could originate from network sources, it is a developer-integrated component rather than an internet-facing service or appliance itself. Public reachability depends entirely on how a developer implements the library within their specific application.

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the openssl_encrypt library allows for improper handling of data validation when a specific dependency is missing. This could potentially allow for the processing of malicious data if an attacker can influence the conditions under which the library operates. The main concern is confirming relevance and exposure within our environments.

Library fails to validate data properly.
Bypasses security checks if a dependency is missing.
Confirm our use and exposure to this library.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by providing specially crafted metadata to an application that uses the `openssl_encrypt` function. If the `jsonschema` library is not installed or if the attacker can manipulate the metadata format to an unknown version, the application will bypass security checks, potentially allowing the processing of malicious data. This could lead to a critical impact on the application's integrity and confidentiality.

No `jsonschema` library installed.
Malformed or unknown metadata format.
Bypass schema checks, process malicious data.

Live Threat

Current exploitation, exposure, and threat context

When the `jsonschema` library is not installed, `openssl_encrypt` may silently accept malformed metadata, bypassing all schema checks. This could allow malicious data to be processed, depending on how the library is integrated into an application.

System metadata could be affected.
Malformed or unknown metadata may be accepted.
Potentially impacts data integrity and processing.

Operational Fix

Recommended remediation, mitigation, and detection steps

The `openssl_encrypt` function's lack of JSON schema validation when the `jsonschema` library is absent creates a critical risk. Application owners and platform teams are likely responsible for managing this library's integration and ensuring proper security configurations. The immediate first step is to identify all applications using this function, assess their exposure and criticality, and then plan for remediation.

Application owners should own the issue.
Verify `jsonschema` library installation.
Plan remediation during maintenance windows.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the openssl_encrypt library used for?

The openssl_encrypt library is a developer-integrated component used within applications to handle data encryption and processing tasks. It relies on specific dependencies, such as the jsonschema library, to ensure that the metadata it processes conforms to expected formats before the application acts upon that data.

How does CVE-2026-74875 allow a security bypass?

This vulnerability, classified as CWE-345 (Insufficient Verification of Data Authenticity), occurs because the library silently skips JSON schema validation if the jsonschema package is missing. By creating an environment without this dependency or submitting unknown metadata formats, the library fails to verify the incoming data, effectively bypassing the security checks intended to catch malicious or malformed input.

Do I need specific attacker conditions to trigger this flaw?

Yes. An attacker must be able to influence the metadata provided to an application using the affected library. The vulnerability is triggered when the jsonschema library is absent or when an attacker supplies metadata with an unrecognized format version. Simply having the library installed and operating in a standard, fully configured environment does not inherently trigger this specific failure.

Is my application at risk if it uses openssl_encrypt?

Halo Surface Signal indicates that public reachability depends entirely on how developers integrate this library into their applications. Because it is a code-level component rather than a standalone service, you should evaluate if your application processes data from untrusted network sources, as this increases the likelihood that an attacker could reach the vulnerable function.

How should I respond to CVE-2026-74875?

Your first step is to perform an inventory of all internal applications that include the openssl_encrypt library. Once identified, verify whether the jsonschema dependency is correctly installed and configured in those environments. If it is missing, prioritize updating your dependency management or application configuration to ensure validation is active before the next maintenance window.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.