CVE-2020-8443Network attack vector

Remote service crash via syslog cleaning overflow

Published Jan 30, 2020 · Updated Aug 4, 2024

OSSEC-HIDS 2.7 through 3.5.0 has an off-by-one heap overflow in ossec-analysisd allowing authenticated remote agents to crash the service. The OS_CleanMSG function advances the log pointer two bytes past a closing bracket when a crafted syslog message ends immediately there, causing a heap out-of-bounds access during decoding. Exploitation requires an authenticated agent able to send a matching syslog message through ossec-remoted; the documented consequence is process instability or service interruption, with memory corruption potentially enabling broader impact.

CVSS severity9.8
Critical
EPSS probability2.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OSSEC-HIDS 2.7 through 3.5.0 has an off-by-one heap overflow in ossec-analysisd allowing authenticated remote agents to crash the service. The OS_CleanMSG function advances the log pointer two bytes past a closing bracket when a crafted syslog message ends immediately there, causing a heap out-of-bounds access during decoding. Exploitation requires an authenticated agent able to send a matching syslog message through ossec-remoted; the documented consequence is process instability or service interruption, with memory corruption potentially enabling broader impact.

The record

CVE
CVE-2020-8443
Published
Jan 30, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-193, CWE-787, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 30, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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

Weakness, pattern, technique

CWE-193Off-by-one Error
CWE-787Out-of-bounds Write
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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