CVE-2021-35290: File Upload vulnerability in balerocms-src 0.8.3 allows remote attackers to run arbitrary code via rich text e

This month

HIGH 7.2DOWNGRADE

CVE-2021-35290 is a high-severity flaw (CVSS 7.2) affecting balero cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

File Upload vulnerability in balerocms-src 0.8.3 allows remote attackers to run arbitrary code via rich text editor on /admin/main/mod-blog page.

Why this priority

High severity

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

Risk facts

CVSS score	7.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.9% (top 40%)
CISA exploited list	No
Weakness	CWE-434
Published	2023-02-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: balero cms project

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

Am I affected?

Timeline

2023-02-24 21:15 UTCPublished CVE record published
2026-06-17 03:57 UTCUpdated Record last modified

balero cms project balero cms DOWNGRADE

Affected: 0.8.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.8.3

1. Check installed version

apt-cache policy balero-cms || rpm -q balero-cms || balero-cms --version

2. No fixed release: DOWNGRADE to a release before 0.8.3 (Debian / Ubuntu)

apt-cache madison balero-cms sudo apt install balero-cms=<VERSION_BEFORE_0.8.3> sudo apt-mark hold balero-cms

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

dnf --showduplicates list balero-cms sudo dnf downgrade balero-cms-<VERSION_BEFORE_0.8.3> sudo dnf versionlock add balero-cms

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-2021-35290?

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

Is CVE-2021-35290 being exploited?

CVE-2021-35290 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-2021-35290 affect?

CVE-2021-35290 affects balero cms. Severity is high (CVSS 7.2). File Upload vulnerability in balerocms-src 0.8.3 allows remote attackers to run arbitrary code via rich text editor on /admin/main/mod-blog page.

How urgent is CVE-2021-35290?

Priority 40/100. High severity

References

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