CVE-2021-33483: An issue was discovered in CommentsService.ashx in OnyakTech Comments Pro 3.8

Routine

MEDIUM 5.4DOWNGRADE

CVE-2021-33483 is a medium-severity flaw (CVSS 5.4) affecting onyaktech comments pro. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in CommentsService.ashx in OnyakTech Comments Pro 3.8. The comment posting functionality allows an attacker to add an XSS payload to the JSON request that will execute when users visit the page with the comment.

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	0.6% (top 51%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-09-07
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: onyaktech comments pro project

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

Am I affected?

Timeline

2021-09-07 05:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

onyaktech comments pro project onyaktech comments pro DOWNGRADE

Affected: 3.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.8

1. Check installed version

apt-cache policy onyaktech-comments-pro || rpm -q onyaktech-comments-pro || onyaktech-comments-pro --version

2. No fixed release: DOWNGRADE to a release before 3.8 (Debian / Ubuntu)

apt-cache madison onyaktech-comments-pro sudo apt install onyaktech-comments-pro=<VERSION_BEFORE_3.8> sudo apt-mark hold onyaktech-comments-pro

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

dnf --showduplicates list onyaktech-comments-pro sudo dnf downgrade onyaktech-comments-pro-<VERSION_BEFORE_3.8> sudo dnf versionlock add onyaktech-comments-pro

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-2021-33483?

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

Is CVE-2021-33483 being exploited?

CVE-2021-33483 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-2021-33483 affect?

CVE-2021-33483 affects onyaktech comments pro. Severity is medium (CVSS 5.4). An issue was discovered in CommentsService.ashx in OnyakTech Comments Pro 3.8. The comment posting functionality allows an attacker to add an XSS payload to the JSON request that will execute when users visit the page with the comment.

How urgent is CVE-2021-33483?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2021-33484 HIGH 7.5 DOWNGRADE An issue was discovered in CommentsService.ashx in OnyakTech Comments Pro 3.8

References

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