CVE-2026-21449: Bagisto/bagisto Bagisto Is Vulnerable To SSTI Vulnerability

HIGH
Advisory Identifier: GHSA-mqhg-v22x-pqj8
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CVSS 8.8
CWE-1336
Published
Advisory Summary

CVE-2026-21449 is a HIGH (CVSS 8.8) bagisto is vulnerable to ssti vulnerability (CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine) affecting Bagisto/bagisto libraries in the Packagist ecosystem. The issue involves bagisto is vulnerable to ssti via name parameters provided by non-admin low-privilege users. Remediation is available by upgrading affected packages to version 2.3.10.

CVE-2026-21449 at a Glance

CVE Identifier CVE-2026-21449
GHSA Identifier GHSA-mqhg-v22x-pqj8
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
Affected Product Bagisto/bagisto
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-21449

To remediate this vulnerability, upgrade all affected Bagisto/bagisto dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

bagisto/bagisto fixed: 2.3.10 
Upgrade bagisto/bagisto to 2.3.10
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for bagisto/bagisto

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-21449, inspect your project dependencies for Bagisto/bagisto:

inspect dependencies for bagisto/bagisto

Analyze the terminal output to locate any version of Bagisto/bagisto in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.3.10), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine, where the product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. In Bagisto/bagisto, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary SSTI is possible via first name and last name parameters provided by lowest-privileged users. ### Details 1. Go to `http://127.0.0.1:8000/` and login or signup 2. Go to `http://127.0.0.1:8000/customer/account/profile` 3. Now edit the first name and last name to {{7*7}} 4. Notice it appears as 49 ### POC - Video attached with the report: https://github.com/user-attachments/assets/f93932b5-2a57-4f34-897e-4151a5168912 ### Impact This can lead to RCE, command injection.

CVE-2026-21449 Affected Bagisto/bagisto Versions

1 component(s)
Fixed Versions:
2.3.10
Product / Package Ecosystem Affected Versions Fixed Version
bagisto/bagisto
 Packagist
< 2.3.10
2.3.10

References

GitHub Advisory / Wiki ADVISORY
https://github.com/bagisto/bagisto/security/advisories/GHSA-mqhg-v22x-pqj8
NVD — CVE-2026-21449 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21449
Security Fix Commit FIX COMMIT
https://github.com/bagisto/bagisto/commit/4144931da0014c696f9126132ce44d7cfbdb2761
Bagisto/bagisto Source Repository REPOSITORY
https://github.com/bagisto/bagisto
Bagisto/bagisto Release RELEASE
https://github.com/bagisto/bagisto/releases/tag/v2.3.10

Frequently Asked Questions

What is CVE-2026-21449?
CVE-2026-21449 is a security vulnerability in Bagisto/bagisto involving Bagisto is vulnerable to SSTI via name parameters provided by non-admin low-privilege users under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine.
Which Bagisto/bagisto versions are affected?
Affected versions include releases prior to 2.3.10 across affected packages: bagisto/bagisto.
What version fixes CVE-2026-21449?
Upgrading to 2.3.10 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bagisto/bagisto affected?
Yes, bagisto/bagisto is affected in releases prior to 2.3.10. Upgrade your dependency to 2.3.10 or later.
What is the CVSS score of CVE-2026-21449?
CVE-2026-21449 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-21449?
CVE-2026-21449 is classified under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine (The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.).
How can I check Packagist dependencies for CVE-2026-21449?
Run the dependency tree command: 'inspect dependencies for bagisto/bagisto'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mqhg-v22x-pqj8",
  "modified" : "2026-01-08T21:36:05Z",
  "published" : "2026-01-02T22:51:40Z",
  "aliases" : [ "CVE-2026-21449" ],
  "summary" : "Bagisto is vulnerable to SSTI via name parameters provided by non-admin low-privilege users",
  "details" : "### Summary\nSSTI is possible via first name and last name parameters provided by lowest-privileged users.\n### Details\n1. Go to `http://127.0.0.1:8000/` and login or signup \n2. Go to `http://127.0.0.1:8000/customer/account/profile`\n3. Now edit the first name and last name to {{7*7}}\n4. Notice it appears as 49\n\n### POC\n- Video attached with the report: https://github.com/user-attachments/assets/f93932b5-2a57-4f34-897e-4151a5168912\n\n### Impact\nThis can lead to RCE, command injection.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "bagisto/bagisto"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.3.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/bagisto/bagisto/security/advisories/GHSA-mqhg-v22x-pqj8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-21449"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bagisto/bagisto/commit/4144931da0014c696f9126132ce44d7cfbdb2761"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/bagisto/bagisto"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bagisto/bagisto/releases/tag/v2.3.10"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1336" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-02T22:51:40Z",
    "nvd_published_at" : "2026-01-02T21:16:02Z"
  }
}