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Fencer Vulns
medium 5.9

CVE-2020-12105 json

OpenConnect through 8.08 mishandles negative return values from X509_check_ function calls, which might assist attackers in performing man-…

published 2020-04-23 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4421

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

OpenConnect through 8.08 mishandles negative return values from X509_check_ function calls, which might assist attackers in performing man-in-the-middle attacks.

Patch / fix

  • 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 SP1 7.08-6.6.1
  • openconnect SLE Workstation Extension 12 SP5, SLE Workstation Extension 12 SP4 7.08-3.9.1

suse advisories SUSE-SU-2024:0317-1SUSE-SU-2020:1337-1SUSE-SU-2020:1264-1

  • openconnect openSUSE Tumbleweed 8.10-2.6
  • openconnect openSUSE Leap 15.1 7.08-lp151.6.6.1

opensuse advisories openSUSE-SU-2024:11114-1openSUSE-SU-2020:0694-1

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-2020-12105 updated cvss 5.9

openconnect: incorrect use of negative return values from X509_check_ functions can lead to MITM attacks

  • 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

1.74% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns 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.