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Fencer Vulns
high 7.0

CVE-2020-4067 json

Improper Initialization in coturn

published 2020-06-29 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-25319

cvss
7.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

In coturn before version 4.5.1.3, there is an issue whereby STUN/TURN response buffer is not initialized properly. There is a leak of information between different client connections. One client (an attacker) could use their connection to intelligently query coturn to get interesting bytes in the padding bytes from the connection of another client. This has been fixed in 4.5.1.3.

Patch / fix

  • coturn_project coturn 4.5.1.3
  • coturn Debian 14, Debian 13, Debian 12 4.5.1.3-1

debian advisories DEBIAN-CVE-2020-4067

  • coturn Ubuntu 16.04 LTS 4.5.0.3-1ubuntu0.3
  • coturn Ubuntu 18.04 LTS 4.5.0.7-1ubuntu2.18.04.2
  • coturn Ubuntu 20.04 LTS 4.5.1.1-1.1ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-4067

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • coturn openSUSE Tumbleweed 4.5.2-2.2
  • coturn openSUSE Leap 15.2 4.5.1.3-lp152.2.3.1

opensuse advisories openSUSE-SU-2024:10696-1openSUSE-SU-2020:0937-1

  • coturn Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 4.5.1.3-r0

alpine advisories ALPINE-CVE-2020-4067

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2020-4067 updated cvss 7.5

coturn: STUN response buffer not initialized properly

  • 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

1.88% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • coturn coturn

Classification

Weakness

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.