CVE-2025-69421 Overview
CVE-2025-69421 is a NULL pointer dereference vulnerability in OpenSSL's PKCS#12 file processing functionality. The vulnerability exists in the PKCS12_item_decrypt_d2i_ex() function, which fails to validate whether the oct parameter is NULL before dereferencing it. When processing a malformed PKCS#12 file via PKCS12_unpack_p7encdata(), an attacker can trigger this condition, causing an application crash.
This vulnerability is classified as a Denial of Service (DoS) issue and cannot be escalated to achieve code execution or memory disclosure. Exploitation requires an attacker to provide a specially crafted malformed PKCS#12 file to an application that processes such files.
Critical Impact
Applications processing PKCS#12 files are vulnerable to denial of service attacks through application crashes when handling malformed input files.
Affected Products
- OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0
- OpenSSL 1.1.1
- OpenSSL 1.0.2
Discovery Timeline
- 2026-01-27 - CVE-2025-69421 published to NVD
- 2026-01-29 - Last updated in NVD database
Technical Details for CVE-2025-69421
Vulnerability Analysis
The vulnerability stems from insufficient input validation in OpenSSL's PKCS#12 processing code. The PKCS12_item_decrypt_d2i_ex() function assumes that the oct parameter will always contain a valid pointer when called. However, when PKCS12_unpack_p7encdata() processes a malformed PKCS#12 file, this parameter can be NULL, leading to a NULL pointer dereference when the function attempts to use this value.
The FIPS modules in OpenSSL versions 3.6, 3.5, 3.4, 3.3, and 3.0 are not affected by this vulnerability because the PKCS#12 implementation exists outside the OpenSSL FIPS module boundary.
Root Cause
The root cause is a missing NULL pointer check (CWE-476) in the PKCS12_item_decrypt_d2i_ex() function. The function does not validate the oct parameter before dereferencing it, creating a condition where malformed input can trigger undefined behavior resulting in application termination.
Attack Vector
An attacker must craft a malformed PKCS#12 file and deliver it to an application that processes PKCS#12 files. The attack is limited to denial of service scenarios as the vulnerability cannot be leveraged for code execution or information disclosure. The malformed file must be specifically constructed to cause the oct parameter to be NULL when PKCS12_unpack_p7encdata() calls the vulnerable function.
The vulnerability can be triggered when applications perform operations such as:
- Importing certificates from PKCS#12 files
- Processing encrypted private keys in PKCS#12 format
- Validating or parsing untrusted PKCS#12 containers
Detection Methods for CVE-2025-69421
Indicators of Compromise
- Unexpected application crashes during PKCS#12 file processing operations
- Core dumps or crash reports indicating NULL pointer dereference in OpenSSL library functions
- Repeated service restarts for applications that handle certificate imports
Detection Strategies
- Monitor application logs for crashes related to PKCS#12 processing or certificate import operations
- Implement file validation and scanning for malformed PKCS#12 files before processing
- Deploy crash monitoring for services that process user-supplied certificate files
- Review system logs for segmentation faults in processes using OpenSSL
Monitoring Recommendations
- Enable crash reporting and analysis for applications processing certificate files
- Monitor for unusual patterns of PKCS#12 file submissions that could indicate exploitation attempts
- Implement rate limiting on certificate import endpoints to reduce denial of service impact
- Set up alerts for repeated crashes in certificate processing services
How to Mitigate CVE-2025-69421
Immediate Actions Required
- Update OpenSSL to the latest patched version for your release branch
- Review applications that process PKCS#12 files from untrusted sources
- Implement input validation before passing PKCS#12 files to OpenSSL functions
- Consider implementing service restart policies to recover from potential crashes
Patch Information
OpenSSL has released security patches addressing this vulnerability across all affected versions. The patches add proper NULL pointer validation in the PKCS12_item_decrypt_d2i_ex() function before dereferencing the oct parameter. For detailed patch information, refer to the OpenSSL Security Advisory.
Multiple commit fixes are available for different OpenSSL versions:
Workarounds
- Validate PKCS#12 files before processing using alternative parsing methods
- Implement application-level crash recovery and service restart mechanisms
- Restrict PKCS#12 file processing to trusted sources only where possible
- Deploy web application firewalls or input validation layers to filter malformed files
# Check OpenSSL version and update
openssl version
# Upgrade to patched version via package manager
# For Debian/Ubuntu:
sudo apt update && sudo apt upgrade openssl
# For RHEL/CentOS:
sudo yum update openssl
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
