CVE-2020-4067Network attack vector

Cross-client information disclosure via uninitialized response padding

Published Jun 29, 2020 · Updated Aug 4, 2024

Information disclosure in coturn before 4.5.1.3 allows remote attackers to read bytes from other clients via crafted STUN/TURN queries. When a response needs padding, ns_turn_msg.c extends its length without zeroing the added bytes, and pooled send buffers retain data from another connection. Network access to the TURN/STUN service is sufficient; disclosure is limited to residual bytes returned in response padding.

CVSS severity7.5
High
EPSS probability1.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in coturn before 4.5.1.3 allows remote attackers to read bytes from other clients via crafted STUN/TURN queries. When a response needs padding, ns_turn_msg.c extends its length without zeroing the added bytes, and pooled send buffers retain data from another connection. Network access to the TURN/STUN service is sufficient; disclosure is limited to residual bytes returned in response padding.

The record

CVE
CVE-2020-4067
Published
Jun 29, 2020
Updated
Aug 4, 2024
Vendor
coturn
Product
coturn
Classifications
CWE-665, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 29, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 5.1.1, < 6.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

coturn · coturnversion=>= 5.1.1, < 6.0.0

Published CVSS scores

7.5Canonical Ubuntu SecurityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-665Improper Initialization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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