CVE-2018-20422: Discuz! DiscuzX 3.4, when WeChat login is enabled, allows remote attackers to bypass authentication by leverag

This week

HIGH 8.1REMOTEDOWNGRADE

CVE-2018-20422 is a high-severity flaw (CVSS 8.1) affecting discuzx. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Discuz! DiscuzX 3.4, when WeChat login is enabled, allows remote attackers to bypass authentication by leveraging a non-empty #wechat#common_member_wechatmp to gain login access to an account via a plugin.php ac=wxregister request (the attacker does not have control over which account will be accessed).

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-287
Published	2018-12-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: comsenz

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

Am I affected?

Timeline

2018-12-24 04:29 UTCPublished CVE record published
2026-06-17 01:52 UTCUpdated Record last modified

comsenz discuzx DOWNGRADE

Affected: x3.4

Fixed in: no fixed release known

Safe to downgrade to: a release before x3.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before x3.4 (Debian / Ubuntu)

apt-cache madison discuzx sudo apt install discuzx=<VERSION_BEFORE_x3.4> sudo apt-mark hold discuzx

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

dnf --showduplicates list discuzx sudo dnf downgrade discuzx-<VERSION_BEFORE_x3.4> sudo dnf versionlock add discuzx

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-2018-20422?

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

Is CVE-2018-20422 being exploited?

CVE-2018-20422 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-2018-20422 affect?

CVE-2018-20422 affects discuzx. Severity is high (CVSS 8.1). Discuz! DiscuzX 3.4, when WeChat login is enabled, allows remote attackers to bypass authentication by leveraging a non-empty #wechat#common_member_wechatmp to gain login access to an account via a plugin.php ac=wxregister request (the atta

How urgent is CVE-2018-20422?

Priority 56/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2024-30884 HIGH 7.1 DOWNGRADE Reflected Cross-Site Scripting (XSS) vulnerability in Discuz! version X3.4 20220811, allows remote attackers t
CVE-2022-45543 MEDIUM 6.1 DOWNGRADE Cross site scripting (XSS) vulnerability in DiscuzX 3.4 allows attackers to execute arbitrary code via the dat
CVE-2018-5377 CRITICAL 9.8 DOWNGRADE Discuz! DiscuzX X3.4 allows remote attackers to bypass intended access restrictions via the archiver\index.php
CVE-2018-5376 MEDIUM 6.1 DOWNGRADE Discuz! DiscuzX X3.4 has XSS via the include\spacecp\spacecp_upload.php op parameter.
CVE-2018-5375 MEDIUM 6.1 DOWNGRADE Discuz! DiscuzX X3.4 has XSS via the include\spacecp\spacecp_space.php appid parameter in a delete action.

References

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