A Server Side Template Injection (SSTI) was discovered in the SEOmatic plugin before 3.1.4 for Craft CMS, because requests that don't match
A Server Side Template Injection (SSTI) was discovered in the SEOmatic plugin before 3.1.4 for Craft CMS, because requests that don't match any elements incorrectly generate the canonicalUrl, and can lead to execution of Twig code.
- Published
- Aug 6, 2018
- Updated
- Jun 16, 2026
- EPSS
- 33.0% · 98th percentile
- CWE
- CWE-94
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Report tools
Action score
40
Plan
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 10 / 30 · 33.0%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| nystudio107 | seomatic | cpe:2.3:a:nystudio107:seomatic |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- nystudio107 seomaticbefore 3.1.4
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Packagist | nystudio107/craft-seomatic | before 3.1.4 | 3.1.4 |
Same product
nystudio107: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-41749In the SEOmatic plugin up to 3.4.11 for Craft CMS 3, it is possible for unauthenticated attackers to perform a Server-Side Template Injectio44Plan
- CVE-2021-44618A Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic 3.4.12 in src/helpers/UrlHelper.php via the host header39Monitor
- CVE-2020-12790In the SEOmatic plugin before 3.2.49 for Craft CMS, helpers/DynamicMeta.php does not properly sanitize the URL.31Monitor
- CVE-2021-41750A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web scr24Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Packagist:nystudio107/craft-seomatic | 3.1.4 | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×1
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | webapps | 2018-07-31 |
| Proof-of-concept repository on GitHub | stars:1 | 2024-05-15 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-7 d
- Published
- TodaySep 30, 2026+2977 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-94 · Improper Control of Generation of Code ('Code Injection')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- ha.cker.info/exploitation-of-server-side-template-injection-with-craft-cms-plguin-seomatic/
- github.com/nystudio107/craft-seomatic/commit/1e7d1d084ac3a89e7ec70620f2749110508d1ce1
- github.com/nystudio107/craft-seomatic/releases/tag/3.1.4
- twitter.com/nystudio107/status/1021847835418009605
- twitter.com/nystudio107/status/1021855169515057152
Vendor advisories and official records. Exploit/PoC links are deliberately left out.