How severe is CVE-2019-6991?

CVE-2019-6991 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-2019-6991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-6991?

CVE-2019-6991 affects Zoneminder. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-6991?

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-2019-6991 published?

CVE-2019-6991 was published on 2019-01-28 and last updated on 2026-06-17.

CVE-2019-6991

CVE-2019-6991 is a critical-severity vulnerability in Zoneminder 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Zoneminder
Published: 2019-01-28
Last modified: 2026-06-17

Description

A classic Stack-based buffer overflow exists in the zmLoadUser() function in zm_user.cpp of the zmu binary in ZoneMinder through 1.32.3, allowing an unauthenticated attacker to execute code via a long username.

Frequently asked questions

What is CVE-2019-6991?: A classic Stack-based buffer overflow exists in the zmLoadUser() function in zm_user.cpp of the zmu binary in ZoneMinder through 1.32.3, allowing an unauthenticated attacker to execute code via a long username.
How severe is CVE-2019-6991?: CVE-2019-6991 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-2019-6991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-6991?: CVE-2019-6991 affects Zoneminder. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-6991?: 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-2019-6991 published?: CVE-2019-6991 was published on 2019-01-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zoneminder:zoneminder:*:*:*:*:*:*:*:*

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