pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version 26.0.0, if a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception, this would result in a connection being accepted. If a user was relying on this callback for any security-sensitive behavior, this could allow bypassing it. Starting in version 26.0.0, unhandled exceptions now result in rejecting the connection.

The remote SUSE Linux SLES12 host has packages installed that are affected by a vulnerability as referenced in the SUSE- SU-2026:1582-1 advisory.

    This update for python-pyOpenSSL fixes the following issue:

    - CVE-2026-27448: unhandled exception can result in connection not being cancelled (bsc#1259804).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:1192-1 advisory.

    - CVE-2026-27448: unhandled exception can result in connection not being cancelled (bsc#1259804).
    - CVE-2026-27459: large cookie value can lead to a buffer overflow (bsc#1259808).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-5697f4e025 advisory.

    Update to version 26.0.0

    - Added support for using aws-lc instead of OpenSSL.
    - Properly raise an error if a DTLS cookie callback returned a cookie       longer than DTLS1_COOKIE_LENGTH bytes. Previously this would result in       a buffer-overflow. Credit to dark_haxor for reporting the issue.
      CVE-2026-27459
    - Added OpenSSL.SSL.Connection.get_group_name to determine which group       name was negotiated.
    - Context.set_tlsext_servername_callback now handles exceptions raised       in the callback by calling sys.excepthook and returning a fatal TLS       alert. Previously, exceptions were silently swallowed and the       handshake would proceed as if the callback had succeeded. Credit to       Leury Castillo for reporting this issue. CVE-2026-27448


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:20419-1 advisory.

    - CVE-2026-27448: unhandled exception can result in connection not being cancelled (bsc#1259804).
    - CVE-2026-27459: large cookie value can lead to a buffer overflow (bsc#1259808).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8115-1 advisory.

    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)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version     26.0.0, if a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception,     this would result in a connection being accepted. If a user was relying on this callback for any security-     sensitive behavior, this could allow bypassing it. Starting in version 26.0.0, unhandled exceptions now     result in rejecting the connection. (CVE-2026-27448)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
310223	SUSE SLES12 Security Update : python-pyOpenSSL (SUSE-SU-2026:1582-1)	Nessus	SuSE Local Security Checks	medium
305283	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : python-pyOpenSSL (SUSE-SU-2026:1192-1)	Nessus	SuSE Local Security Checks	critical
304349	Fedora 44 : pyOpenSSL (2026-5697f4e025)	Nessus	Fedora Local Security Checks	critical
304227	openSUSE 16 Security Update : python-pyOpenSSL (openSUSE-SU-2026:20419-1)	Nessus	SuSE Local Security Checks	critical
303750	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 : pyOpenSSL vulnerabilities (USN-8115-1)	Nessus	Ubuntu Local Security Checks	critical
302891	Linux Distros Unpatched Vulnerability : CVE-2026-27448	Nessus	Misc.	medium

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