CVE-2025-68160 Heap out-of-bounds write in BIO_f_linebuffer on short writes
Heap out-of-bounds write in OpenSSL's line-buffering filter can cause crashes and denial of service when specific non-default configurations are used.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68160?
CVE-2025-68160 is a medium-severity memory corruption vulnerability in Openssl Openssl, published on 27 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Issue summary: Writing large, newline-free data into a BIO chain using the line-buffering filter where the next BIO performs short writes can trigger a heap-based out-of-bounds write.
Impact summary: This out-of-bounds write can cause memory corruption which typically results in a crash, leading to Denial of Service for an application.
The line-buffering BIO filter (BIO_f_linebuffer) is not used by default in TLS/SSL data paths. In OpenSSL command-line applications, it is typically only pushed onto stdout/stderr on VMS systems. Third-party applications that explicitly use this filter with a BIO chain that can short-write and that write large, newline-free data influenced by an attacker would be affected. However, the circumstances where this could happen are unlikely to be under attacker control, and BIO_f_linebuffer is unlikely to be handling non-curated data controlled by an attacker. For that reason the issue was assessed as Low severity.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the BIO implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.
Weakness: CWE-787
Which versions are affected by CVE-2025-68160?
It affects 1 product.
Products include Openssl Openssl.
How do I fix CVE-2025-68160?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-68160 being exploited?
There is no known exploitation of CVE-2025-68160 in the wild and no public exploit code.
Other vulnerabilities in Openssl Openssl
Sources
Also known as ALPINE-CVE-2025-68160, AZL-75281, AZL-75780, AZL-75887, AZL-76125, AZL-76164 and 13 more.