CVE-2019-16108: Phpbb/phpbb PhpBB Arbitrary CSS Injection Vulnerability

HIGH
Advisory Identifier: GHSA-8hc2-hvrc-x4qr
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CVSS 7.5
CWE-94
Published
Advisory Summary

CVE-2019-16108 is a HIGH (CVSS 7.5) phpbb arbitrary css injection vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Phpbb/phpbb libraries in the Packagist ecosystem. The issue involves phpbb arbitrary css injection. Remediation is available by upgrading affected packages to version 3.2.8.

CVE-2019-16108 at a Glance

CVE Identifier CVE-2019-16108
GHSA Identifier GHSA-8hc2-hvrc-x4qr
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Phpbb/phpbb
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 7.5

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

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

How to Fix CVE-2019-16108

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

phpbb/phpbb fixed: 3.2.8 
Upgrade phpbb/phpbb to 3.2.8
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 phpbb/phpbb

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-16108, inspect your project dependencies for Phpbb/phpbb:

inspect dependencies for phpbb/phpbb

Analyze the terminal output to locate any version of Phpbb/phpbb in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.8), 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Phpbb/phpbb, 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

phpBB 3.2.7 allows adding an arbitrary Cascading Style Sheets (CSS) token sequence to a page through BBCode.

CVE-2019-16108 Affected Phpbb/phpbb Versions

1 component(s)
Fixed Versions:
3.2.8
Product / Package Ecosystem Affected Versions Fixed Version
phpbb/phpbb
 Packagist
≥ 3.2.7
< 3.2.8
All 1 versions
3.2.7
3.2.8

References

NVD — CVE-2019-16108 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-16108
Phpbb/phpbb Source Repository REPOSITORY
https://github.com/phpbb/phpbb-app
www.phpbb.com/community/viewtopic... WEB
https://www.phpbb.com/community/viewtopic.php?t=2523271

Frequently Asked Questions

What is CVE-2019-16108?
CVE-2019-16108 is a security vulnerability in Phpbb/phpbb involving phpBB arbitrary CSS injection under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Phpbb/phpbb versions are affected?
Affected versions include releases prior to 3.2.8 across affected packages: phpbb/phpbb.
What version fixes CVE-2019-16108?
Upgrading to 3.2.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is phpbb/phpbb affected?
Yes, phpbb/phpbb is affected in releases prior to 3.2.8. Upgrade your dependency to 3.2.8 or later.
What is the CVSS score of CVE-2019-16108?
CVE-2019-16108 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2019-16108?
CVE-2019-16108 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Packagist dependencies for CVE-2019-16108?
Run the dependency tree command: 'inspect dependencies for phpbb/phpbb'. 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-8hc2-hvrc-x4qr",
  "modified" : "2024-04-24T17:44:30Z",
  "published" : "2022-05-24T17:12:01Z",
  "aliases" : [ "CVE-2019-16108" ],
  "summary" : "phpBB arbitrary CSS injection",
  "details" : "phpBB 3.2.7 allows adding an arbitrary Cascading Style Sheets (CSS) token sequence to a page through BBCode.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "phpbb/phpbb"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.2.7"
      }, {
        "fixed" : "3.2.8"
      } ]
    } ],
    "versions" : [ "3.2.7" ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-16108"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/phpbb/phpbb-app"
  }, {
    "type" : "WEB",
    "url" : "https://www.phpbb.com/community/viewtopic.php?t=2523271"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-24T17:44:30Z",
    "nvd_published_at" : "2020-03-20T00:17:00Z"
  }
}