Medium severity · published Jan 27, 2026
CVE-2025-68160
Heap out-of-bounds write in BIO_f_linebuffer on short writes
4.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenSSL · OpenSSL
3.6.0 before 3.6.1; 3.5.0 before 3.5.5; 3.4.0 before 3.4.4; 3.3.0 before 3.3.6; 3.0.0 before 3.0.19; 1.1.1 before 1.1.1ze; +1 more · source: vendor, NVD
SS
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem · Siemens
0 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-68160
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-68160
Patch
https://github.com/openssl/openssl/commit/384011202af92605d926fafe4a0bcd6b65d162ad
Patch
https://github.com/openssl/openssl/commit/475c466ef2fbd8fc1df6fae1c3eed9c813fc8ff6
Patch
https://github.com/openssl/openssl/commit/4c96fbba618e1940f038012506ee9e21d32ee12c
Patch
https://github.com/openssl/openssl/commit/6845c3b6460a98b1ec4e463baa2ea1a63a32d7c0
Patch
https://github.com/openssl/openssl/commit/68a7cd2e2816c3a02f4d45a2ce43fc04fac97096
Vendor Advisory
https://openssl-library.org/news/secadv/20260127.txt
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