CVE-2018-1000059: ValidFormBuilder version 4.5.4 contains a PHP Object Injection vulnerability in Valid Form unserialize method

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2018-1000059 is a critical-severity flaw (CVSS 9.8) affecting validform builder. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ValidFormBuilder version 4.5.4 contains a PHP Object Injection vulnerability in Valid Form unserialize method that can result in Possible to execute unauthorised system commands remotely and disclose file contents in file system.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-502
Published	2018-02-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: validformbuilder

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

Am I affected?

Timeline

2018-02-09 23:29 UTCPublished CVE record published
2026-06-17 01:32 UTCUpdated Record last modified

validformbuilder validform builder DOWNGRADE

Affected: 4.5.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.5.4

1. Check installed version

apt-cache policy validform-builder || rpm -q validform-builder || validform-builder --version

2. No fixed release: DOWNGRADE to a release before 4.5.4 (Debian / Ubuntu)

apt-cache madison validform-builder sudo apt install validform-builder=<VERSION_BEFORE_4.5.4> sudo apt-mark hold validform-builder

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

dnf --showduplicates list validform-builder sudo dnf downgrade validform-builder-<VERSION_BEFORE_4.5.4> sudo dnf versionlock add validform-builder

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-2018-1000059?

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

Is CVE-2018-1000059 being exploited?

CVE-2018-1000059 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-2018-1000059 affect?

CVE-2018-1000059 affects validform builder. Severity is critical (CVSS 9.8). ValidFormBuilder version 4.5.4 contains a PHP Object Injection vulnerability in Valid Form unserialize method that can result in Possible to execute unauthorised system commands remotely and disclose file contents in file system.

How urgent is CVE-2018-1000059?

Priority 58/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

References

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