How severe is CVE-2018-19991?

CVE-2018-19991 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-2018-19991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-19991?

CVE-2018-19991 affects Verynginx Project Verynginx. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-19991?

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-2018-19991 published?

CVE-2018-19991 was published on 2018-12-10 and last updated on 2026-06-17.

CVE-2018-19991

CVE-2018-19991 is a critical-severity vulnerability in Verynginx Project Verynginx 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-755.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-755
Affected product: Verynginx Project Verynginx
Published: 2018-12-10
Last modified: 2026-06-17

Description

VeryNginx 0.3.3 allows remote attackers to bypass the Web Application Firewall feature because there is no error handler (for get_uri_args or get_post_args) to block the API misuse described in CVE-2018-9230.

Frequently asked questions

What is CVE-2018-19991?: VeryNginx 0.3.3 allows remote attackers to bypass the Web Application Firewall feature because there is no error handler (for get_uri_args or get_post_args) to block the API misuse described in CVE-2018-9230.
How severe is CVE-2018-19991?: CVE-2018-19991 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-2018-19991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-19991?: CVE-2018-19991 affects Verynginx Project Verynginx. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-19991?: 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-2018-19991 published?: CVE-2018-19991 was published on 2018-12-10 and last updated on 2026-06-17.

References

https://github.com/alexazhou/VeryNginx/issues/218

Affected products (1)

cpe:2.3:a:verynginx_project:verynginx:0.3.3:*:*:*:*:nginx:*:*

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