AUGUST 4, 2026
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Case File

CVE-2026-27459

CRITICAL · CVSS 9.8 EPSS 0.70% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-03-18 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.8. It affects OpenSSL. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-27459
Severity
CRITICAL
CVSS
9.8
EPSS
0.70%
OpenSSL

Original NVD Description

pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, 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. Starting in version 26.0.0, cookie values that are too long are now rejected.

Related CVEs

Other vulnerabilities affecting the same vendor(s)