HOME VULNERABILITIESCVE-2021-27903

CRITICAL

CVE-2021-27903

CWE-862Published: June 30, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

An issue was discovered in Craft CMS before 3.6.7. In some circumstances, a potential Remote Code Execution vulnerability existed on sites that did not restrict administrative changes (if an attacker were somehow able to hijack an administrator's session).

Technical Analysis

CVE-2021-27903 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

craftcms1 product(s)

craft cms

Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/craftcms/cms/commit/c17728fa0bec11d3b82c34defe0930ed409aec38

PATCHhttps://github.com/craftcms/cms/commit/c17728fa0bec11d3b82c34defe0930ed409aec38

ADVISORYhttps://github.com/craftcms/cms/blob/develop/CHANGELOG.md#367---2021-02-23

ADVISORYhttps://github.com/craftcms/cms/blob/develop/CHANGELOG.md#security

ADVISORYhttps://github.com/craftcms/cms/blob/develop/CHANGELOG.md#367---2021-02-23

ADVISORYhttps://github.com/craftcms/cms/blob/develop/CHANGELOG.md#security

All References (6)

→

https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#367---2021-02-23Release Notes · Third Party Advisory

→

https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#securityRelease Notes · Third Party Advisory

→

https://github.com/craftcms/cms/commit/c17728fa0bec11d3b82c34defe0930ed409aec38Patch · Third Party Advisory

→

https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#367---2021-02-23Release Notes · Third Party Advisory

→

https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#securityRelease Notes · Third Party Advisory

→

https://github.com/craftcms/cms/commit/c17728fa0bec11d3b82c34defe0930ed409aec38Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-27903

CVSS Score9.8 / 10

SeverityCRITICAL

WeaknessCWE-862

CISA KEVNo

Affected1 vendor(s)

PublishedJun 30, 2021

Related CVEs (CWE-862)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2021-27903 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.

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