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Advisory severityHigh8.1Red Hat Linux

High [CVE-2026-19445] Use-after-free of a server-side SSLContext when sni_callback switches contexts

This high-severity Red Hat Linux advisory covers CVE-2026-19445; related products: Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-19445 Source published Source updated

VulniPulse record published Record updated

CVE-2026-19445
Related products & platforms
Red Hat LinuxUnclassified
Open source advisory

Summary

Use-after-free of a server-side SSLContext when sni_callback switches contexts. Red Hat rates this important (CVSS 8.1).

Weakness: CWE-416. Red Hat lists fixing advisory RHSA-2026:77028 with package rhui5/cds-rhel9:1791978528, python3.14-0:3.14.8-1.el9_8, python3.14-0:3.14.8-1.el10_2, python3.12-0:3.12.15-1.el9_8.

Affected products named by the advisory: Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8.

Is CVE-2026-19445 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-19445 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-19445?

Upgrade to a fixed release named by Red Hat:

  • rhui5/cds-rhel9:1791978528
  • python3.14-0:3.14.8-1.el9_8
  • python3.14-0:3.14.8-1.el10_2
  • python3.12-0:3.12.15-1.el9_8
  • python3-15-main-3.15.0~rc2-1.1.hum1
  • python3.12-0:3.12.15-1.el10_2
  • python3.12-0:3.12.15-2.el8_10
  • rhui5/installer-rhel9:1791964013
  • rhui5/rhua-rhel9:1791978693
  • rhui5/cds-kubernetes-rhel9:1791978534
  • python3-0:3.6.8-79.el8_10
  • RHSA-2026:77028

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 28 days ago·verify at source

Fixed versions
  • rhui5/cds-rhel9:1791978528
  • python3.14-0:3.14.8-1.el9_8
  • python3.14-0:3.14.8-1.el10_2
  • python3.12-0:3.12.15-1.el9_8
  • python3-15-main-3.15.0~rc2-1.1.hum1
  • python3.12-0:3.12.15-1.el10_2
  • python3.12-0:3.12.15-2.el8_10
  • rhui5/installer-rhel9:1791964013
  • rhui5/rhua-rhel9:1791978693
  • rhui5/cds-kubernetes-rhel9:1791978534
  • python3-0:3.6.8-79.el8_10
  • RHSA-2026:77028

Official advisory · high-confidence parse· fetched 28 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Restrict Python TLS servers that use SSLContext.sni_callback to trusted clients. Keep a strong reference to every SSLContext that registers an SNI callback for the lifetime of the server so the original context cannot be garbage-collected while connections remain open. Prefer wrapping the listening socket with a long-lived SSLContext; that common pattern is not affected. Host heap allocator hardening increases the difficulty of turning the use-after-free into reliable code execution but does not prevent process crashes.

Official advisory · high-confidence parse· fetched 28 days ago·verify at source

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