Back Linuxsecurity Ubuntu 25.10 pyOpenSSL Critical Fix for Denial of Service CVE-2026
A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 25.10 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: Several security issues were fixed in pyOpenSSL. Software Description: - pyopenssl: Python wrapper around the OpenSSL library Details: It was discovered that pyOpenSSL incorrectly handled exceptions in the tlsext_servername callback. This could result in connections being accepted after an exception, contrary to expectations. (CVE-2026-27448) It was discovered that pyOpenSSL incorrectly handled the DTLS cookie generation callback. If a callback provided cookie values greater than 256 bytes, an attacker could use this issue to cause pyOpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 25.10. (CVE-2026-27459)
A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 25.10 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: Several security issues were fixed in pyOpenSSL. Software Description: - pyopenssl: Python wrapper around the OpenSSL library Details: It was discovered that pyOpenSSL incorrectly handled exceptions in the tlsext_servername callback. This could result in connections being accepted after an exception, contrary to expectations. (CVE-2026-27448) It was discovered that pyOpenSSL incorrectly handled the DTLS cookie generation callback. If a callback provided cookie values greater than 256 bytes, an attacker could use this issue to cause pyOpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 25.10. (CVE-2026-27459)
The problem can be corrected by updating your system to the following package versions: Ubuntu 25.10 python3-openssl 25.0.0-1ubuntu0.1 Ubuntu 24.04 LTS python3-openssl 23.2.0-1ubuntu0.1 Ubuntu 22.04 LTS python3-openssl 21.0.0-1ubuntu0.1 In general, a standard system update will make all the necessary changes.
The problem can be corrected by updating your system to the following package versions: Ubuntu 25.10 python3-openssl 25.0.0-1ubuntu0.1 Ubuntu 24.04 LTS python3-openssl 23.2.0-1ubuntu0.1 Ubuntu 22.04 LTS python3-openssl 21.0.0-1ubuntu0.1 In general, a standard system update will make all the necessary changes.
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