CVE-2026-27459 pyOpenSSL DTLS cookie callback buffer overflow

🗓️ 17 Mar 2026 23:34:28Reported by GoogleType

osv

osv🔗 osv.dev👁 1 Views

pyOpenSSL DTLS cookie callback overflow occurs if cookie exceeds 256 bytes; fixed in version 26.0.0.

Reporter	Title	Published	Views	Family All 127
IBM Security Bulletins	Security Bulletin: IBM Watson Speech Services Cartridge is vulnerable to a security bypass in pyOpenSSL [CVE-2026-27448, CVE-2026-27459]	21 May 202615:10	–	ibm
IBM Security Bulletins	Security Bulletin: pyOpenSSL TLS SNI Callback Exception Handling Flaw Allows Security Bypass	4 May 202612:18	–	ibm
IBM Security Bulletins	Security Bulletin: Multiple Vulnerabilities in pyOpenSSL bundled with IBM Fusion, IBM Fusion HCI, and IBM Fusion Data Cataloging	18 May 202622:19	–	ibm
IBM Security Bulletins	Security Bulletin: IBM SOAR QRadar Plugin App is vulnerable to using components with known vulnerabilities	6 May 202616:21	–	ibm
ATTACKERKB	CVE-2026-27459	17 Mar 202623:34	–	attackerkb
AlpineLinux	CVE-2026-27459	17 Mar 202623:34	–	alpinelinux
CBLMariner	CVE-2026-27459 affecting package pyOpenSSL for versions less than 24.2.1-2	25 Mar 202622:53	–	cbl_mariner
Chainguard	CVE-2026-27459 vulnerabilities	18 Mar 202601:17	–	cgr
Circl	CVE-2026-27459	23 Mar 202616:05	–	circl
CNNVD	pyOpenSSL 安全漏洞	17 Mar 202600:00	–	cnnvd

Source	Link
github	www.github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst
github	www.github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27459.json
github	www.github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4
nvd	www.nvd.nist.gov/vuln/detail/CVE-2026-27459
github	www.github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408

06 Jun 2026 18:29Current

5.9Medium risk

Vulners AI Score5.9

CVSS 49.2

EPSS0.00027

py openssl dtls protocol cookie callback buffer overflow long cookies