CVE-2021-33853: A Cross-Site Scripting (XSS) attack can cause arbitrary code (javascript) to run in a user’s browser while the

Routine

MEDIUM 5.4DOWNGRADE

CVE-2021-33853 is a medium-severity flaw (CVSS 5.4) affecting x2crm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Cross-Site Scripting (XSS) attack can cause arbitrary code (javascript) to run in a user’s browser while the browser is connected to a trusted website. As the vehicle for the attack, the application targets the users and not the application itself. Additionally, the XSS payload is executed when the user attempts to access any page of the CRM.

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 53%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-03-16
Last modified	2026-06-17

Publisher (CNA): Cyber Security Works Pvt. Ltd. · Vendor: x2engine

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

Am I affected?

Timeline

2022-03-16 15:15 UTCPublished CVE record published
2026-06-17 03:55 UTCUpdated Record last modified

x2engine x2crm DOWNGRADE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

1. Check installed version

apt-cache policy x2crm || rpm -q x2crm || x2crm --version

2. No fixed release: DOWNGRADE to a release before 8.0 (Debian / Ubuntu)

apt-cache madison x2crm sudo apt install x2crm=<VERSION_BEFORE_8.0> sudo apt-mark hold x2crm

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

dnf --showduplicates list x2crm sudo dnf downgrade x2crm-<VERSION_BEFORE_8.0> sudo dnf versionlock add x2crm

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-2021-33853?

x2crm: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-33853 being exploited?

CVE-2021-33853 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-2021-33853 affect?

CVE-2021-33853 affects x2crm. Severity is medium (CVSS 5.4). A Cross-Site Scripting (XSS) attack can cause arbitrary code (javascript) to run in a user’s browser while the browser is connected to a trusted website. As the vehicle for the attack, the application targets the users and not the applicati

How urgent is CVE-2021-33853?

Priority 36/100. Public exploit reference

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CVE-2021-27288 MEDIUM 6.1 DOWNGRADE Cross Site Scripting (XSS) in X2Engine X2CRM v7.1 allows remote attackers to obtain sensitive information by i
CVE-2020-21088 MEDIUM 4.8 UPGRADE Cross Site Scripting (XSS) in X2engine X2CRM v7.1 and older allows remote attackers to obtain sensitive inform

References

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