How severe is CVE-2020-18663?

CVE-2020-18663 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-18663 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-18663?

CVE-2020-18663 affects Sir Gnuboard. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-18663?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-18663 published?

CVE-2020-18663 was published on 2021-06-24 and last updated on 2026-06-17.

CVE-2020-18663

CVE-2020-18663 is a medium-severity vulnerability in Sir Gnuboard with a CVSS 3.x base score of 6.1. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Sir Gnuboard
Published: 2021-06-24
Last modified: 2026-06-17

Description

Cross Site Scripting (XSS) vulnerability in gnuboard5 <=v5.3.2.8 via the act parameter in bbs/move_update.php.

Frequently asked questions

What is CVE-2020-18663?: Cross Site Scripting (XSS) vulnerability in gnuboard5 <=v5.3.2.8 via the act parameter in bbs/move_update.php.
How severe is CVE-2020-18663?: CVE-2020-18663 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-18663 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-18663?: CVE-2020-18663 affects Sir Gnuboard. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-18663?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-18663 published?: CVE-2020-18663 was published on 2021-06-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:sir:gnuboard:*:*:*:*:*:*:*:*

More vulnerabilities in Sir Gnuboard

CVE-2020-18662 — Critical (CVSS 9.8): SQL Injection vulnerability in gnuboard5 <=v5.3.2.8 via the table_prefix parameter in install_db.php.
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CVE-2024-41475 — High (CVSS 8.8): Gnuboard g6 6.0.7 is vulnerable to Session hijacking due to a CORS misconfiguration.
CVE-2022-1252 — High (CVSS 8.2): Use of a Broken or Risky Cryptographic Algorithm in GitHub repository gnuboard/gnuboard5 prior to and including 5.5.5.…
CVE-2022-44216 — High (CVSS 7.5): Gnuboard 5.5.4 and 5.5.5 is vulnerable to Insecure Permissions. An attacker can change password of all users without…
CVE-2011-4066 — High (CVSS 7.5): SQL injection vulnerability in bbs/tb.php in Gnuboard 4.33.02 and earlier allows remote attackers to execute arbitrary…

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