CVE-2023-31903: GuppY CMS 6.00.10 is vulnerable to Unrestricted File Upload which allows remote attackers to execute arbitrary

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2023-31903 is a critical-severity flaw (CVSS 9.8) affecting guppy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GuppY CMS 6.00.10 is vulnerable to Unrestricted File Upload which allows remote attackers to execute arbitrary code by uploading a php file.

Why this priority

Critical 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	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-434
Published	2023-05-17
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: freeguppy

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

Am I affected?

Timeline

2023-05-17 13:15 UTCPublished CVE record published
2026-06-17 05:57 UTCUpdated Record last modified

freeguppy guppy DOWNGRADE

Affected: 6.00.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.00.10

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 6.00.10 (Debian / Ubuntu)

apt-cache madison guppy sudo apt install guppy=<VERSION_BEFORE_6.00.10> sudo apt-mark hold guppy

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

dnf --showduplicates list guppy sudo dnf downgrade guppy-<VERSION_BEFORE_6.00.10> sudo dnf versionlock add guppy

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-2023-31903?

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

Is CVE-2023-31903 being exploited?

CVE-2023-31903 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-2023-31903 affect?

CVE-2023-31903 affects guppy. Severity is critical (CVSS 9.8). GuppY CMS 6.00.10 is vulnerable to Unrestricted File Upload which allows remote attackers to execute arbitrary code by uploading a php file.

How urgent is CVE-2023-31903?

Priority 65/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

References

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