CVE-2026-21875: ClipBucket v5 is an open source video sharing platform

Q: How do I fix CVE-2026-21875?

clipbucket: upgrade to 5.5.2-191. Exact commands for each OS are on this page.

Q: Is CVE-2026-21875 being exploited?

CVE-2026-21875 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-21875 affect?

CVE-2026-21875 affects clipbucket. Severity is critical (CVSS 9.8). ClipBucket v5 is an open source video sharing platform. Versions 5.5.2-#187 and below allow an attacker to perform Blind SQL Injection through the add comment section within a channel. When adding a comment within a channel, there is a POST

Q: How urgent is CVE-2026-21875?

Priority 67/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-21875 is a critical-severity flaw (CVSS 9.8) affecting clipbucket. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ClipBucket v5 is an open source video sharing platform. Versions 5.5.2-#187 and below allow an attacker to perform Blind SQL Injection through the add comment section within a channel. When adding a comment within a channel, there is a POST request to the /actions/ajax.php endpoint. The obj_id parameter within the POST request to /actions/ajax.php is then used within the user_exists function of the upload/includes/classes/user.class. php file as

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 22%)
CISA exploited list	No
Weakness	CWE-89
Published	2026-01-08
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: oxygenz

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

Am I affected?

Timeline

2026-01-08 00:16 UTCPublished CVE record published
2026-06-17 10:19 UTCUpdated Record last modified

oxygenz clipbucket UPGRADE

Affected: >= 5.3 and < 5.5.2-191

Fixed in: 5.5.2-191

Safe to downgrade to: a release before 5.3

1. Check installed version

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

2. UPGRADE to 5.5.2-191 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade clipbucket

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade clipbucket

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.3 (Debian / Ubuntu)

apt-cache madison clipbucket sudo apt install clipbucket=<VERSION_BEFORE_5.3> sudo apt-mark hold clipbucket

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list clipbucket sudo dnf downgrade clipbucket-<VERSION_BEFORE_5.3> sudo dnf versionlock add clipbucket

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.

Exact fixes by distribution

Fedora ELN · fwupd-efi · FIXED · 1.9-3.eln159 · FEDORA-2026-44fd42db42 · source

sudo dnf upgrade --advisory=FEDORA-2026-44fd42db42

Fedora 46 · crest · FIXED · 3.0.2-1.fc46 · FEDORA-2026-b49adefa8f · source

sudo dnf upgrade --advisory=FEDORA-2026-b49adefa8f

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/MacWarrior/clipbucket-v5/security/advisories/GHSA-crpv-fmc4-j392
Nuclei scan template: ClipBucket v5 <= 5.5.2 - Unauthenticated Blind SQL Injection

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-2026-21875?

clipbucket: upgrade to 5.5.2-191. Exact commands for each OS are on this page.

Is CVE-2026-21875 being exploited?

CVE-2026-21875 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-2026-21875 affect?

CVE-2026-21875 affects clipbucket. Severity is critical (CVSS 9.8). ClipBucket v5 is an open source video sharing platform. Versions 5.5.2-#187 and below allow an attacker to perform Blind SQL Injection through the add comment section within a channel. When adding a comment within a channel, there is a POST

How urgent is CVE-2026-21875?

Priority 67/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2025-62715 MEDIUM 5.4 UPGRADE ClipBucket v5 is an open source video sharing platform
CVE-2025-62709 MEDIUM 6.8 UPGRADE ClipBucket v5 is an open source video sharing platform
CVE-2025-62424 MEDIUM 6.7 UPGRADE ClipBucket is a web-based video-sharing platform
CVE-2025-62423 MEDIUM 6.7 UPGRADE ClipBucket V5 provides open source video hosting with PHP
CVE-2025-62429 HIGH 7.2 UPGRADE ClipBucket v5 is an open source video sharing platform

References

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