CVE-2020-23356: dmin/kernel/api/login.class.phpin in nibbleblog v3.7.1c allows type juggling for login bypass because == is us

This month

HIGH 7.5REMOTEDOWNGRADE

CVE-2020-23356 is a high-severity flaw (CVSS 7.5) affecting nibbleblog. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

dmin/kernel/api/login.class.phpin in nibbleblog v3.7.1c allows type juggling for login bypass because == is used instead of === for password hashes, which mishandles hashes that begin with 0e followed by exclusively numerical characters.

Why this priority

High severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Published	2021-01-27
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

2021-01-27 16:15 UTCPublished CVE record published
2026-06-17 03:04 UTCUpdated Record last modified

nibbleblog nibbleblog DOWNGRADE

Affected: 3.7.1c

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.7.1c

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.7.1c (Debian / Ubuntu)

apt-cache madison nibbleblog sudo apt install nibbleblog=<VERSION_BEFORE_3.7.1c> sudo apt-mark hold nibbleblog

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

dnf --showduplicates list nibbleblog sudo dnf downgrade nibbleblog-<VERSION_BEFORE_3.7.1c> 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-2020-23356?

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

Is CVE-2020-23356 being exploited?

CVE-2020-23356 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-2020-23356 affect?

CVE-2020-23356 affects nibbleblog. Severity is high (CVSS 7.5). dmin/kernel/api/login.class.phpin in nibbleblog v3.7.1c allows type juggling for login bypass because == is used instead of === for password hashes, which mishandles hashes that begin with 0e followed by exclusively numerical characters.

How urgent is CVE-2020-23356?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

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
CVE-2018-16604 HIGH 7.2 DOWNGRADE An issue was discovered in Nibbleblog v4.0.5

References

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