How severe is CVE-2020-27988?

No CVSS score has been assigned to CVE-2020-27988 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2020-27988?

Affected package information for CVE-2020-27988 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2020-27988?

No fixed release is recorded for CVE-2020-27988 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2020-27988 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2020-27988 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2020-27988 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-27988 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-27988?

CVE-2020-27988 has an EPSS (Exploit Prediction Scoring System) score of 91.3%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2020-27988?

CVE-2020-27988 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2020-27988 published, and has it been updated?

CVE-2020-27988 was published on November 16, 2020 and was last updated on August 4, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Not in CISA KEV

CVE-2020-27988

CVE-2020-27988 is a Cross-site Scripting (XSS) vulnerability. EPSS puts its 30-day exploitation probability at 91.3% (100th percentile). No vendor fix is recorded yet; mitigation options are listed below.

Nagios XI before 5.7.5 is vulnerable to XSS in Manage Users (Username field).

Published

Nov 16, 2020

Updated

Aug 4, 2024

Affected

1 product

Patched

See advisory

Exploits

None indexed

Exploitation data as of Sep 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

91.3%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

Nagios XI before 5.7.5 is vulnerable to XSS in Manage Users (Username field).

Affected Products

1 product · 1 configurations

Application

nagios xinagios

< 5.7.5

range

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2020-27988 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

Nagios XI before 5.7.5 is vulnerable to XSS in Manage Users (Username field).

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CVE-2020-27988

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

Frequently Asked Questions

Is CVE-2020-27988 in your dependencies?