CVE-2021-20686: Cross-site scripting vulnerability in Kagemai 0.8.8 allows remote attackers to inject an arbitrary script via

Routine

MEDIUM 6.1DOWNGRADE

CVE-2021-20686 is a medium-severity flaw (CVSS 6.1) affecting kagemai. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting vulnerability in Kagemai 0.8.8 allows remote attackers to inject an arbitrary script via unspecified vectors.

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	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-04-07
Last modified	2026-06-17

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

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

Am I affected?

Timeline

2021-04-07 08:15 UTCPublished CVE record published
2026-06-17 03:34 UTCUpdated Record last modified

daifukuya kagemai DOWNGRADE

Affected: 0.8.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.8.8

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.8.8 (Debian / Ubuntu)

apt-cache madison kagemai sudo apt install kagemai=<VERSION_BEFORE_0.8.8> sudo apt-mark hold kagemai

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

dnf --showduplicates list kagemai sudo dnf downgrade kagemai-<VERSION_BEFORE_0.8.8> sudo dnf versionlock add kagemai

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-2021-20686?

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

Is CVE-2021-20686 being exploited?

CVE-2021-20686 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-2021-20686 affect?

CVE-2021-20686 affects kagemai. Severity is medium (CVSS 6.1). Cross-site scripting vulnerability in Kagemai 0.8.8 allows remote attackers to inject an arbitrary script via unspecified vectors.

How urgent is CVE-2021-20686?

Priority 35/100. No elevated risk signals yet.

Related CVEs

CVE-2021-20687 HIGH 8.8 DOWNGRADE Cross-site request forgery (CSRF) vulnerability in Kagemai 0.8.8 allows remote attackers to hijack the authent
CVE-2021-20685 MEDIUM 6.1 DOWNGRADE Cross-site scripting vulnerability in Kagemai 0.8.8 allows remote attackers to inject an arbitrary script via

References

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