How severe is CVE-2020-8443?

CVE-2020-8443 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-8443 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-8443?

CVE-2020-8443 affects Ossec. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-8443?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-8443 published?

CVE-2020-8443 was published on 2020-01-30 and last updated on 2026-06-17.

CVE-2020-8443

CVE-2020-8443 is a critical-severity vulnerability in Ossec with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-193.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-193
Affected product: Ossec
Published: 2020-01-30
Last modified: 2026-06-17

Description

In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulnerable to an off-by-one heap-based buffer overflow during the cleaning of crafted syslog msgs (received from authenticated remote agents and delivered to the analysisd processing queue by ossec-remoted).

Frequently asked questions

What is CVE-2020-8443?: In OSSEC-HIDS 2.7 through 3.5.0, the server component responsible for log analysis (ossec-analysisd) is vulnerable to an off-by-one heap-based buffer overflow during the cleaning of crafted syslog msgs (received from authenticated remote agents and delivered to the analysisd processing queue by ossec-remoted).
How severe is CVE-2020-8443?: CVE-2020-8443 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-8443 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-8443?: CVE-2020-8443 affects Ossec. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-8443?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-8443 published?: CVE-2020-8443 was published on 2020-01-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ossec:ossec:*:*:*:*:*:*:*:*

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Other CWE-193 (Off-by-one Error) vulnerabilities

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