How severe is CVE-2023-35784?

CVE-2023-35784 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-35784 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-35784?

CVE-2023-35784 primarily affects Openbsd Libressl. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-35784?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2023-35784 published?

CVE-2023-35784 was published on 2023-06-16 and last updated on 2026-06-17.

CVE-2023-35784

CVE-2023-35784 is a critical-severity vulnerability in Openbsd Libressl with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-415.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (57th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-415
Affected product: Openbsd Libressl
Published: 2023-06-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2023-35784?: 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.
How severe is CVE-2023-35784?: CVE-2023-35784 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-35784 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-35784?: CVE-2023-35784 primarily affects Openbsd Libressl. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-35784?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2023-35784 published?: CVE-2023-35784 was published on 2023-06-16 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:openbsd:libressl:*:*:*:*:*:*:*:*
cpe:2.3:o:openbsd:openbsd:7.2:*:*:*:*:*:*:*
cpe:2.3:o:openbsd:openbsd:7.3:*:*:*:*:*:*:*

More vulnerabilities in Openbsd Libressl

CVE-2021-46880 — Critical (CVSS 9.8): x509/x509_verify.c in LibreSSL before 3.4.2, and OpenBSD before 7.0 errata 006, allows authentication bypass because an…
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CVE-2015-5333 — High (CVSS 7.5): Memory leak in the OBJ_obj2txt function in LibreSSL before 2.3.1 allows remote attackers to cause a denial of service…
CVE-2014-9424 — High (CVSS 7.5): Double free vulnerability in the ssl_parse_clienthello_use_srtp_ext function in d1_srtp.c in LibreSSL before 2.1.2…
CVE-2018-8970 — High (CVSS 7.4): The int_x509_param_set_hosts function in lib/libcrypto/x509/x509_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support…
CVE-2019-25049 — High (CVSS 7.1): LibreSSL 2.9.1 through 3.2.1 has an out-of-bounds read in asn1_item_print_ctx (called from asn1_template_print_ctx).

All CVEs affecting Openbsd Libressl →

Other CWE-415 (Double Free) vulnerabilities

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CVE-2020-37239 — Critical (CVSS 9.8): libbabl 0.1.62 contains a broken double free detection vulnerability that allows attackers to bypass memory safety…
CVE-2026-43011 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When…
CVE-2026-31609 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in…
CVE-2026-31608 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: server: avoid double-free in…

Browse all CWE-415 (Double Free) vulnerabilities →