CVE-2026-27459
March 16, 2026
If a user provided callback to "set_cookie_generate_callback" returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Cookie values that are too long are now rejected.
Affected Packages
pyopenssl (CONDA):
Affected version(s) >=22.0.0 <26.0.0Fix Suggestion:
Update to version 26.0.0https://github.com/pyca/pyopenssl.git (GITHUB):
Affected version(s) >=0.14a2 <26.0.0Fix Suggestion:
Update to version 26.0.0pyopenssl (PYTHON):
Affected version(s) >=22.0.0 <26.0.0Fix Suggestion:
Update to version 26.0.0Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
7.2
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
Exploit Maturity
UNREPORTED
CVSS v3
Base Score:
8.1
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
