CVE-2018-0535: Cross-site scripting vulnerability in PHP 2chBBS version bbs18c allows an attacker to inject arbitrary web scr

Routine

MEDIUM 6.1DOWNGRADE

CVE-2018-0535 is a medium-severity flaw (CVSS 6.1) affecting php 2chbbs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting vulnerability in PHP 2chBBS version bbs18c allows an attacker to inject arbitrary web script or HTML via unspecified vectors.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-79
Published	2018-03-22
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: php 2chbbs project

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

Am I affected?

Timeline

2018-03-22 13:29 UTCPublished CVE record published
2026-06-17 01:31 UTCUpdated Record last modified

php 2chbbs project php 2chbbs DOWNGRADE

Affected: bbs18c

Fixed in: no fixed release known

Safe to downgrade to: a release before bbs18c

1. Check installed version

apt-cache policy php-2chbbs || rpm -q php-2chbbs || php-2chbbs --version

2. No fixed release: DOWNGRADE to a release before bbs18c (Debian / Ubuntu)

apt-cache madison php-2chbbs sudo apt install php-2chbbs=<VERSION_BEFORE_bbs18c> sudo apt-mark hold php-2chbbs

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

dnf --showduplicates list php-2chbbs sudo dnf downgrade php-2chbbs-<VERSION_BEFORE_bbs18c> sudo dnf versionlock add php-2chbbs

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-2018-0535?

php 2chbbs: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-0535 being exploited?

CVE-2018-0535 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-2018-0535 affect?

CVE-2018-0535 affects php 2chbbs. Severity is medium (CVSS 6.1). Cross-site scripting vulnerability in PHP 2chBBS version bbs18c allows an attacker to inject arbitrary web script or HTML via unspecified vectors.

How urgent is CVE-2018-0535?

Priority 35/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

References

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