HOMEVULNERABILITIESCVE-2020-12823
CRITICAL

CVE-2020-12823

CWE-120Published: May 12, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2020-12823 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
infradead1 product(s)
openconnect
openSUSE1 product(s)
leap
Source: NVD CPE · 7 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://gitlab.com/openconnect/openconnect/-/merge_requests/108
PATCHhttps://gitlab.com/openconnect/openconnect/-/merge_requests/108
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00039.html
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00056.html
ADVISORYhttps://bugs.gentoo.org/721570
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/05/msg00015.html
ADVISORYhttps://security.gentoo.org/glsa/202006-15
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00039.html
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00056.html
ADVISORYhttps://bugs.gentoo.org/721570
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/05/msg00015.html
ADVISORYhttps://security.gentoo.org/glsa/202006-15

All References (18)

→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00039.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00056.htmlMailing List · Third Party Advisory
→
https://bugs.gentoo.org/721570Exploit · Third Party Advisory
→
https://gitlab.com/openconnect/openconnect/-/merge_requests/108Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/05/msg00015.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/25MFX4AZE7RDCUWOL4ZOE73YBOPUMQDX/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AYSXLXAPXD2T73T6JMHI5G2WP7KHAGMN/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BEVTIH5UFX35CC7MVSYBGRM3D66ACFD5/
→
https://security.gentoo.org/glsa/202006-15Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00039.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00056.htmlMailing List · Third Party Advisory
→
https://bugs.gentoo.org/721570Exploit · Third Party Advisory
→
https://gitlab.com/openconnect/openconnect/-/merge_requests/108Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/05/msg00015.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/25MFX4AZE7RDCUWOL4ZOE73YBOPUMQDX/

Quick Facts

CVE IDCVE-2020-12823
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-120
CISA KEVNo
Affected4 vendor(s)
PublishedMay 12, 2020

Related CVEs (CWE-120)

CVE-2008-3496
10.0
CVE-2022-20827
10.0
CVE-2001-0191
10.0
CVE-2012-10035
10.0
CVE-2022-31481
10.0
CVE-2024-25139
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-12823 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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