CVE-2020-5540: Cross-site scripting vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to inject arbitrar

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MEDIUM 6.1DOWNGRADE

CVE-2020-5540 is a medium-severity flaw (CVSS 6.1) affecting cybermail. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to inject arbitrary script or HTML via a specially crafted URL.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-08-25
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: cybersolutions

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

Am I affected?

Timeline

2020-08-25 03:15 UTCPublished CVE record published
2026-06-17 03:21 UTCUpdated Record last modified

cybersolutions cybermail DOWNGRADE

Affected: 6.0 · 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

1. Check installed version

apt-cache policy cybermail || rpm -q cybermail || cybermail --version

2. No fixed release: DOWNGRADE to a release before 6.0 (Debian / Ubuntu)

apt-cache madison cybermail sudo apt install cybermail=<VERSION_BEFORE_6.0> sudo apt-mark hold cybermail

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

dnf --showduplicates list cybermail sudo dnf downgrade cybermail-<VERSION_BEFORE_6.0> sudo dnf versionlock add cybermail

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.

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-2020-5540?

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

Is CVE-2020-5540 being exploited?

CVE-2020-5540 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-2020-5540 affect?

CVE-2020-5540 affects cybermail. Severity is medium (CVSS 6.1). Cross-site scripting vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to inject arbitrary script or HTML via a specially crafted URL.

How urgent is CVE-2020-5540?

Priority 40/100. No elevated risk signals yet.

Related CVEs

CVE-2020-5541 MEDIUM 6.1 DOWNGRADE Open redirect vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to redirect users to arbi
CVE-2020-11734 MEDIUM 6.1 DOWNGRADE cgi-bin/go in CyberSolutions CyberMail 5 or later allows XSS via the ACTION parameter.

References

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