CVE-2020-36619

Process memory corruption via unescaped FLEX text

Published Dec 19, 2022 · Updated Apr 15, 2025

Format string injection in multimon-ng before 1.2.0 allows attackers to corrupt process memory via crafted FLEX message text. The add_ch function in demod_flex.c copies decoded percent characters into an output buffer that unixinput.c::_verbprintf later treats as a format string. Reachability requires processing an attacker-controlled FLEX transmission; the upstream patch identifies stack corruption without establishing code execution.

CVSS severity9.8
Critical
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format string injection in multimon-ng before 1.2.0 allows attackers to corrupt process memory via crafted FLEX message text. The add_ch function in demod_flex.c copies decoded percent characters into an output buffer that unixinput.c::_verbprintf later treats as a format string. Reachability requires processing an attacker-controlled FLEX transmission; the upstream patch identifies stack corruption without establishing code execution.

The record

CVE
CVE-2020-36619
Published
Dec 19, 2022
Updated
Apr 15, 2025
Vendor
Multimon-ng Project
Product
multimon-ng
Classifications
CWE-134
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 19, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

Multimon-ng Project · multimon-ngversion=n/a

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5VulDBCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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