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HIGH

CVE-2026-84783

CVSS v3

7.5

HIGH

EPSS Score

—

exploit probability

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

Issue summary: The first concurrent use of the same X.509 certificate by several threads may cause its cached extension data to be freed while another thread is still using it. Impact summary: A remote, unauthenticated peer could crash a multi-threaded TLS client, or a multi-threaded TLS server that requests client certificates, if the first certificate chains built to the same trusted CA certificate are built by several connections at the same time. This is a use-after-free read, which is like

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-09-29
Last Modified
2026-09-29

Frequently asked questions

What is CVE-2026-84783?

Issue summary: The first concurrent use of the same X.509 certificate by several threads may cause its cached extension data to be freed while another thread is still using it. Impact summary: A remote, unauthenticated peer could crash a multi-threaded TLS client, or a multi-threaded TLS server that requests client certificates, if the first certificate chains built to the same trusted CA certificate are built by several connections at the same time. This is a use-after-free read, which is like

Is CVE-2026-84783 actively exploited?

Active exploitation of CVE-2026-84783 has not been confirmed.

What is the CVSS score for CVE-2026-84783?

CVE-2026-84783 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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