SB2026081845 - Buffer overflow in pyOpenSSL

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Main Vulnerability Database SB2026081845

SB2026081845 - Buffer overflow in pyOpenSSL

Published: August 18, 2026

Security Bulletin ID SB2026081845
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Buffer overflow (CVE-ID: CVE-2026-27459)

CWE-ID: CWE-120 - Buffer overflow

CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists because the callback provided to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, causing pyOpenSSL to overflow an OpenSSL-provided buffer. A remote attacker can pass specially crafted data to the application, trigger a buffer overflow and execute arbitrary code on the target system.


Remediation

Install update from vendor's website.

References