CVE-2018-16604: An issue was discovered in Nibbleblog v4.0.5

This month

HIGH 7.2DOWNGRADE

CVE-2018-16604 is a high-severity flaw (CVSS 7.2) affecting nibbleblog. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Nibbleblog v4.0.5. With an admin's username and password, an attacker can execute arbitrary PHP code by changing the username because the username is surrounded by double quotes (e.g., "${phpinfo()}").

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-94
Published	2018-09-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nibbleblog

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

Am I affected?

Timeline

2018-09-06 16:29 UTCPublished CVE record published
2026-06-17 01:44 UTCUpdated Record last modified

nibbleblog nibbleblog DOWNGRADE

Affected: 4.0.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.0.5 (Debian / Ubuntu)

apt-cache madison nibbleblog sudo apt install nibbleblog=<VERSION_BEFORE_4.0.5> sudo apt-mark hold nibbleblog

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

dnf --showduplicates list nibbleblog sudo dnf downgrade nibbleblog-<VERSION_BEFORE_4.0.5> sudo dnf versionlock add nibbleblog

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-2018-16604?

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

Is CVE-2018-16604 being exploited?

CVE-2018-16604 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-2018-16604 affect?

CVE-2018-16604 affects nibbleblog. Severity is high (CVSS 7.2). An issue was discovered in Nibbleblog v4.0.5. With an admin's username and password, an attacker can execute arbitrary PHP code by changing the username because the username is surrounded by double quotes (e.g., "${phpinfo()}").

How urgent is CVE-2018-16604?

Priority 49/100. High severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2020-23356 HIGH 7.5 DOWNGRADE dmin/kernel/api/login.class.phpin in nibbleblog v3.7.1c allows type juggling for login bypass because == is us
CVE-2019-7719 CRITICAL 9.8 DOWNGRADE Nibbleblog 4.0.5 allows eval injection by placing PHP code in the install.php username parameter and then maki
CVE-2018-6470 MEDIUM 5.3 DOWNGRADE Nibbleblog 4.0.5 on macOS defaults to having .DS_Store in each directory, causing DS_Store information to leak

References

← Back to latest CVEs