CVE-2021-42335: Easytest bulletin board management function of online learning platform does not filter special characters

Routine

MEDIUM 5.4DOWNGRADE

CVE-2021-42335 is a medium-severity flaw (CVSS 5.4) affecting easytest online learning test platform. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Easytest bulletin board management function of online learning platform does not filter special characters. After obtaining a user’s privilege, remote attackers can inject JavaScript and execute stored XSS attack.

Why this priority

No elevated risk signals yet

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 52%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-10-15
Last modified	2026-06-17

Publisher (CNA): TWCERT/CC · Vendor: huaju

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

Am I affected?

Timeline

2021-10-15 12:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

huaju easytest online learning test platform DOWNGRADE

Affected: 1705

Fixed in: no fixed release known

Safe to downgrade to: a release before 1705

1. Check installed version

apt-cache policy easytest-online-learning-test-platform || rpm -q easytest-online-learning-test-platform || easytest-online-learning-test-platform --version

2. No fixed release: DOWNGRADE to a release before 1705 (Debian / Ubuntu)

apt-cache madison easytest-online-learning-test-platform sudo apt install easytest-online-learning-test-platform=<VERSION_BEFORE_1705> sudo apt-mark hold easytest-online-learning-test-platform

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

dnf --showduplicates list easytest-online-learning-test-platform sudo dnf downgrade easytest-online-learning-test-platform-<VERSION_BEFORE_1705> sudo dnf versionlock add easytest-online-learning-test-platform

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-2021-42335?

easytest online learning test platform: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-42335 being exploited?

CVE-2021-42335 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-2021-42335 affect?

CVE-2021-42335 affects easytest online learning test platform. Severity is medium (CVSS 5.4). Easytest bulletin board management function of online learning platform does not filter special characters. After obtaining a user’s privilege, remote attackers can inject JavaScript and execute stored XSS attack.

How urgent is CVE-2021-42335?

Priority 31/100. No elevated risk signals yet.

Related CVEs

CVE-2021-42336 MEDIUM 4.3 DOWNGRADE The learning history page of the Easytest is vulnerable by permission bypass
CVE-2021-42334 HIGH 8.8 DOWNGRADE The Easytest contains SQL injection vulnerabilities
CVE-2021-42333 HIGH 8.8 DOWNGRADE The Easytest contains SQL injection vulnerabilities

References

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