CVE-2026-27448

Description

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.

CVSS Metrics

• v4.0•MEDIUM•Score: 6.3CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
• v4.0•LOW•Score: 1.7CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
• v3.1•MEDIUM•Score: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Trends

Current EPSS score: 0.24%• Percentile: 16%

Techniques & Countermeasures

• CWE-636•Not Failing Securely ('Failing Open')

  When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

Affected Systems

• chainguard•airflow-2

  < 2.11.2-r2

• chainguard•airflow-3

  < 3.1.8-r8

• chainguard•authentik

  < 2026.2.1-r4

• chainguard•authentik-fips

  < 2026.2.1-r3

• chainguard•awx

  < 24.6.1-r31

• chainguard•az

  < 2.84.0-r3

• chainguard•datadog-agent-7.71-core-integrations

  all

• chainguard•datadog-agent-7.72-core-integrations

  all

• chainguard•datadog-agent-7.73-core-integrations

  < 7.73.3-r23

• chainguard•datadog-agent-7.74-core-integrations

  < 7.74.1-r24

• chainguard•datadog-agent-7.75-core-integrations

  all

• chainguard•datadog-agent-7.76

  < 7.76.3-r41

• chainguard•datadog-agent-7.76-core-integrations

  < 7.76.3-r32

• chainguard•datadog-agent-7.77-core-integrations

  < 7.77.3-r5

• chainguard•datadog-agent-fips-7.71-core-integrations

  < 7.71.2-r20 | < 7.71.2-r19

• chainguard•datadog-agent-fips-7.72-core-integrations

  all

• chainguard•datadog-agent-fips-7.73-core-integrations

  < 7.73.3-r26

• chainguard•datadog-agent-fips-7.74-core-integrations

  < 7.74.1-r26

• chainguard•datadog-agent-fips-7.75-core-integrations

  all

• chainguard•datadog-agent-fips-7.76-core-integrations

  < 7.76.3-r32

• chainguard•datadog-agent-fips-7.77-core-integrations

  < 7.77.3-r5

• chainguard•datahub-ingestion

  < 1.5.0.1-r0

• chainguard•dbt-snowflake

  all

• chainguard•ggshield

  < 1.51.0-r1

• chainguard•gitlab-toolbox-ce-18.7

  < 18.7.5-r1

• chainguard•gitlab-toolbox-ce-18.8

  < 18.8.5-r2

• chainguard•gitlab-toolbox-ce-18.9

  < 18.9.2-r1

• chainguard•gitlab-toolbox-ce-fips-18.7

  < 18.7.5-r1

• chainguard•gitlab-toolbox-ce-fips-18.8

  < 18.8.5-r1

• chainguard•gitlab-toolbox-ce-fips-18.9

  < 18.9.2-r1

• chainguard•gitlab-toolbox-ce-fips-19.0

  < 19.0.2-r1

• chainguard•keep-api

  < 0.51.0-r0

• chainguard•keep-api-fips

  < 0.51.0-r0

• chainguard•localstack

  < 4.14.0-r4

• chainguard•mitmproxy

  < 12.2.1-r0 | < 12.2.3-r0

• chainguard•py3-cassandra-medusa

  < 0.27.0-r5

• chainguard•py3.13-duplicity

  all

• chainguard•request-1276

  < 0.27.0-r6

• chainguard•superset-5.0

  < 5.0.0-r20

• chainguard•superset-6.0

  < 6.0.0-r4

• wolfi•airflow-3

  < 3.1.8-r8

• wolfi•az

  < 2.84.0-r3

• wolfi•datadog-agent-7.72-core-integrations

  all

• wolfi•datadog-agent-7.73-core-integrations

  < 7.73.3-r23

• wolfi•datadog-agent-7.74-core-integrations

  < 7.74.1-r24

• wolfi•datadog-agent-7.75-core-integrations

  all

• wolfi•datadog-agent-7.76

  < 7.76.3-r41

• wolfi•datadog-agent-7.76-core-integrations

  < 7.76.3-r32

• wolfi•datadog-agent-7.77-core-integrations

  < 7.77.3-r5

• wolfi•ggshield

  < 1.51.0-r1

Showing first 50 affected entries in server-rendered view.

References (10)

• https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424
• https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0
• https://github.com/pyca/pyopenssl
• https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27
• https://nvd.nist.gov/vuln/detail/CVE-2026-27448
• https://www.suse.com/support/update/announcement/2026/suse-su-20263424-1/
• https://bugzilla.suse.com/1259804
• https://www.suse.com/security/cve/CVE-2026-27448
• https://security-tracker.debian.org/tracker/CVE-2026-27448
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27448.json