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Fencer Intel
critical 9.8

CVE-2020-12823 json

OpenConnect 8.09 has a buffer overflow, causing a denial of service (application crash) or possibly unspecified other impact, via crafted c…

published 6y ago modified 4mo ago also EUVD-2020-5106

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.7%
EPSS 4.7% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

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.

Patch / fix

  • openconnect Debian 14, Debian 13, Debian 12 8.10-1

debian advisories DEBIAN-CVE-2020-12823

  • openconnect SLE Workstation Extension 15 SP5, SLE Module for Package Hub 15 SP5, openSUSE Leap 15.5 9.12-150400.15.3.1
  • stoken SLE Workstation Extension 15 SP5, SLE Module for Package Hub 15 SP5, openSUSE Leap 15.5 0.81-150400.13.2.1
  • oath-toolkit SLE Workstation Extension 15 SP5, SLE Module for Package Hub 15 SP5, SLE Module for Basesystem 15 SP5 +1 more 2.6.2-150000.3.5.1
  • openconnect SLE Workstation Extension 15 SP2, SLE Workstation Extension 15 SP1 7.08-6.9.1
  • openconnect SLE Workstation Extension 12 SP5, SLE Workstation Extension 12 SP4 7.08-3.12.1

suse advisories SUSE-SU-2024:0317-1SUSE-SU-2020:1930-1SUSE-SU-2020:1807-1

  • openconnect openSUSE Tumbleweed 8.10-2.6
  • openconnect openSUSE Leap 15.2 7.08-lp152.9.4.2
  • openconnect openSUSE Leap 15.1 7.08-lp151.6.9.1

opensuse advisories openSUSE-SU-2024:11114-1openSUSE-SU-2020:1027-1openSUSE-SU-2020:0997-1

  • openconnect Arch Linux 1:8.10-1

arch linux advisories AVG-1157

Is CVE-2020-12823 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-12823 updated cvss 8.6

openconnect: buffer overflow via crafted certificate data to get_cert_name function in gnutls.c

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.74% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugs.gentoo.org https://bugs.gentoo.org/721570 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.