CVE-2020-24963: An Authenticated Persistent XSS vulnerability was discovered in the Best Support System, tested version v3.0.4

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MEDIUM 5.4DOWNGRADE

CVE-2020-24963 is a medium-severity flaw (CVSS 5.4) affecting best support system. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An Authenticated Persistent XSS vulnerability was discovered in the Best Support System, tested version v3.0.4.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	1.9% (top 21%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-09-04
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: appsbd

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-09-04 16:15 UTCPublished CVE record published
2026-06-17 03:06 UTCUpdated Record last modified

appsbd best support system DOWNGRADE

Affected: 3.0.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.4

1. Check installed version

apt-cache policy best-support-system || rpm -q best-support-system || best-support-system --version

2. No fixed release: DOWNGRADE to a release before 3.0.4 (Debian / Ubuntu)

apt-cache madison best-support-system sudo apt install best-support-system=<VERSION_BEFORE_3.0.4> sudo apt-mark hold best-support-system

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list best-support-system sudo dnf downgrade best-support-system-<VERSION_BEFORE_3.0.4> sudo dnf versionlock add best-support-system

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Best Support System 3.0.4 - 'ticket_body' Persistent XSS (Authenticated)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-24963?

best support system: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-24963 being exploited?

CVE-2020-24963 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-24963 affect?

CVE-2020-24963 affects best support system. Severity is medium (CVSS 5.4). An Authenticated Persistent XSS vulnerability was discovered in the Best Support System, tested version v3.0.4.

How urgent is CVE-2020-24963?

Priority 44/100. Public exploit reference

References

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