CVE-2026-27459
pyOpenSSL DTLS cookie callback buffer overflow
CVE-2026-27459 is fixed in 51 products on 1 platform, first by DEBIAN-CVE-2026-27459, released March 18, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
9.8
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0075
55th percentile
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| kryoptic · Fedora 43 | 1.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| kryoptic-debuginfo · Fedora 43 | 1.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| kryoptic-debugsource · Fedora 43 | 1.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| kryoptic-tools · Fedora 43 | 1.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| kryoptic-tools-debuginfo · Fedora 43 | 1.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| pyOpenSSL · Fedora 43 | 26.0.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| pyOpenSSL-doc · Fedora 43 | 26.0.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| pyopenssl · Debian 13.5 (trixie) | 25.0.0-1+deb13u1 | DEBIAN-CVE-2026-27459 | Mar 18, 2026 |
| pyopenssl · Debian 14 | 26.0.0-1 | DEBIAN-CVE-2026-27459 | Mar 18, 2026 |
| python-cryptography · Fedora 43 | 46.0.5-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| python-cryptography-debugsource · Fedora 43 | 46.0.5-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| python-pyOpenSSL · opensuse-leap 15.6 | 23.2.0-150400.3.13.1 | SUSE-SU-2026:1192-1 | Apr 7, 2026 |
| python-pyOpenSSL · opensuse-leap 16.0 | 25.0.0-160000.3.1 | OPENSUSE-SU-2026:20419-1 | Mar 25, 2026 |
| python-pyOpenSSL · sles 15.6 | 23.2.0-150400.3.13.1 | SUSE-SU-2026:1192-1 | Apr 7, 2026 |
| python-pyOpenSSL · sles 15.7 | 23.2.0-150400.3.13.1 | SUSE-SU-2026:1192-1 | Apr 7, 2026 |
| python-pyOpenSSL · sles 16.0 | 25.0.0-160000.3.1 | SUSE-SU-2026:20930-1 | Mar 25, 2026 |
| python3-cryptography · Fedora 43 | 46.0.5-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| python3-cryptography-debuginfo · Fedora 43 | 46.0.5-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| python3-openssl · Ubuntu 24.04.5 LTS (noble) | 23.2.0-1ubuntu0.1 | python3-openssl 23.2.0-1ubuntu0.1 | Apr 15, 2026 |
| python3-openssl · Ubuntu 25.10 (questing) | 25.0.0-1ubuntu0.1 | python3-openssl 25.0.0-1ubuntu0.1 | Apr 15, 2026 |
| python3-pyOpenSSL · Fedora 43 | 26.0.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1 · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1+default-devel · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1+std-devel · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1-devel · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1_derive · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1_derive+default-devel · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-asn1_derive-devel · Fedora 43 | 0.22.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki · Fedora 43 | 0.12.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki+default-devel · Fedora 43 | 0.12.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki+generate-bindings-devel · Fedora 43 | 0.12.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki+serde-devel · Fedora 43 | 0.12.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-devel · Fedora 43 | 0.12.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-sys · Fedora 43 | 0.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-sys+bindgen-devel · Fedora 43 | 0.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-sys+default-devel · Fedora 43 | 0.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-sys+generate-bindings-devel · Fedora 43 | 0.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-cryptoki-sys-devel · Fedora 43 | 0.5.0-2.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+aead-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+cipher-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+default-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+dsa-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+ec-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+ecdh-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+ecdsa-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+eddsa-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+fpe-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+hkdf-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+keywrap-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+mac-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+num-bigint-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+primality-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+rsa_enc-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+rsa_sig-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof+xdh-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
| rust-wycheproof-devel · Fedora 43 | 0.6.0-1.fc43 | FEDORA-2026-9D5B9F45EC | Mar 19, 2026 |
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