CVE-2020-12823

CRITICALNVD 9.89.8—

9.8

OpenConnect 8.09 has a buffer overflow, causing a denial of service (application crash) or possibly unspecified other impact, via crafted certificate data to get_cert_name in gnutls.c.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 83.3%
KEV: Not listed

Published

May 12, 2020

Last Modified

November 21, 2024

Advisory Details (7)

Auto-updated May 27, 2026

Patch available.

generic

OpenConnect: Multiple vulnerabilities (GLSA 202006-15) — Gentoo security

https://security.gentoo.org/glsa/202006-15

generic

[SECURITY] Fedora 31 Update: openconnect-8.10-1.fc31 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BEVTIH5UFX35CC7MVSYBGRM3D66ACFD5/

generic

[SECURITY] Fedora 32 Update: openconnect-8.10-1.fc32 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AYSXLXAPXD2T73T6JMHI5G2WP7KHAGMN/

generic

[SECURITY] Fedora 30 Update: openconnect-8.10-1.fc30 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/25MFX4AZE7RDCUWOL4ZOE73YBOPUMQDX/

generic Patch Available

[SECURITY] [DLA 2212-1] openconnect security update

https://lists.debian.org/debian-lts-announce/2020/05/msg00015.html

generic

gnutls: prevent buffer overflow in get_cert_name (!108) · Merge requests · OpenConnect VPN projects / OpenConnect · GitLab

https://gitlab.com/openconnect/openconnect/-/merge_requests/108

generic

721570 – net-vpn/ocserv-1.0.1: test failures on arm64 due to stack smashing detection with LD_PRELOAD=libsocket_wrapper.so

https://bugs.gentoo.org/721570

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-120Buffer Copy without Checking Size (Classic Buffer Overflow)

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:39 UTCepss_batch
2026-05-27 03:42 UTCEG score recompute
2026-05-27 03:42 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2020-12823?

CVE-2020-12823 is a critical vulnerability published on May 12, 2020. OpenConnect 8.09 has a buffer overflow, causing a denial of service (application crash) or possibly unspecified other impact, via crafted certificate data to getcertname in gnutls.c.

When was CVE-2020-12823 disclosed?

CVE-2020-12823 was first published in the National Vulnerability Database on May 12, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2020-12823 actively exploited?

CVE-2020-12823 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 83.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2020-12823?

CVE-2020-12823 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2020-12823?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-12823, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2020-12823

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CVE-2020-12823

📅 Published

🔄 Last Modified

📋 Advisory Details (7)

OpenConnect: Multiple vulnerabilities (GLSA 202006-15) — Gentoo security

[SECURITY] Fedora 31 Update: openconnect-8.10-1.fc31 - package-announce - Fedora mailing-lists

[SECURITY] Fedora 32 Update: openconnect-8.10-1.fc32 - package-announce - Fedora mailing-lists

[SECURITY] Fedora 30 Update: openconnect-8.10-1.fc30 - package-announce - Fedora mailing-lists

[SECURITY] [DLA 2212-1] openconnect security update

gnutls: prevent buffer overflow in get_cert_name (!108) · Merge requests · OpenConnect VPN projects / OpenConnect · GitLab

721570 – net-vpn/ocserv-1.0.1: test failures on arm64 due to stack smashing detection with LD_PRELOAD=libsocket_wrapper.so

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2020-12823?

Published

Last Modified

Advisory Details (7)

Frequently asked(5)