What’s Vulnerable › Vulnerabilities

CVE-2023-35784

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-06-16 · updated 2026-06-17
• Weakness: CWE-415

Description

A double free or use after free could occur after SSL_clear in OpenBSD 7.2 before errata 026 and 7.3 before errata 004, and in LibreSSL before 3.6.3 and 3.7.x before 3.7.3. NOTE: OpenSSL is not affected.

Affected products

• OpenBSD Libressl: before 3.6.3; from 3.7.0 before 3.7.3 — fixed in 3.6.3, 3.7.3
• OpenBSD: 7.2, 7.3

How to fix

Upgrade to a fixed version: OpenBSD Libressl 3.6.3, 3.7.3. Check the vendor advisory for mitigations.

References

• https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-3.6.3-relnotes.txt
• https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-3.7.3-relnotes.txt
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/026_ssl.patch.sig
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.3/common/004_ssl.patch.sig
• https://github.com/libressl/openbsd/commit/e42d8f4b21a8a498e2eabbffe4c7b7d4ef7cec54
• https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-3.6.3-relnotes.txt
• https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-3.7.3-relnotes.txt
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/026_ssl.patch.sig
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.3/common/004_ssl.patch.sig
• https://github.com/libressl/openbsd/commit/e42d8f4b21a8a498e2eabbffe4c7b7d4ef7cec54

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