CVE-2025-68160
📋 TL;DR
This vulnerability in OpenSSL's line-buffering BIO filter allows heap-based out-of-bounds writes when processing large, newline-free data with short writes in the BIO chain. It primarily affects third-party applications that explicitly use the BIO_f_linebuffer filter with attacker-controlled data, potentially causing crashes and denial of service. The vulnerability is assessed as low severity due to the unlikely combination of required conditions.
💻 Affected Systems
- OpenSSL
📦 What is this software?
Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →Openssl by Openssl
OpenSSL is a robust, commercial-grade toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It provides cryptographic functions and is one of the most widely used libraries for implementing secure communications in applications worldwide.
Learn more about Openssl →⚠️ Risk & Real-World Impact
Worst Case
Memory corruption leading to application crash and denial of service, potentially allowing arbitrary code execution if the memory corruption can be controlled by an attacker.
Likely Case
Application crash and denial of service in specific configurations where BIO_f_linebuffer is used with attacker-controlled data and short writes occur.
If Mitigated
No impact if BIO_f_linebuffer is not used, or if applications don't process attacker-controlled data through this filter with short writes.
🎯 Exploit Status
Exploitation requires: 1) Application explicitly uses BIO_f_linebuffer filter, 2) BIO chain performs short writes, 3) Large, newline-free attacker-controlled data, 4) These conditions under attacker control - making exploitation unlikely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available via the provided GitHub commit references
Vendor Advisory: https://github.com/openssl/openssl/commit/384011202af92605d926fafe4a0bcd6b65d162ad
Restart Required: Yes
Instructions:
1. Update OpenSSL to a patched version. 2. Recompile any applications linked against OpenSSL. 3. Restart affected services. 4. Verify the fix using version checks.
🔧 Temporary Workarounds
Disable BIO_f_linebuffer usage
allAvoid using the BIO_f_linebuffer filter in applications, especially with untrusted data
Review application code and remove BIO_f_linebuffer usage where possible
Input validation and size limits
allImplement input validation and size limits for data processed through BIO chains
Implement application-level input validation and size restrictions
🧯 If You Can't Patch
- Avoid using BIO_f_linebuffer filter in applications
- Implement strict input validation and size limits for data processed through BIO chains
🔍 How to Verify
Check if Vulnerable:
Check OpenSSL version with 'openssl version' and verify if it's in the affected version rangeCheck Version:
openssl versionVerify Fix Applied:
Verify OpenSSL version is updated beyond vulnerable versions and check for the specific commit fixes in the build📡 Detection & Monitoring
Log Indicators:
- Application crashes or segmentation faults in processes using OpenSSL BIO_f_linebuffer
- Memory corruption errors in application logs
Network Indicators:
- Sudden service unavailability of applications using OpenSSL
SIEM Query:
Process crashes with OpenSSL library in stack trace OR Application logs containing 'segmentation fault' with OpenSSL context🔗 References
- https://github.com/openssl/openssl/commit/384011202af92605d926fafe4a0bcd6b65d162ad
- https://github.com/openssl/openssl/commit/475c466ef2fbd8fc1df6fae1c3eed9c813fc8ff6
- https://github.com/openssl/openssl/commit/4c96fbba618e1940f038012506ee9e21d32ee12c
- https://github.com/openssl/openssl/commit/6845c3b6460a98b1ec4e463baa2ea1a63a32d7c0
- https://github.com/openssl/openssl/commit/68a7cd2e2816c3a02f4d45a2ce43fc04fac97096
- https://openssl-library.org/news/secadv/20260127.txt
