Directory traversal vulnerability in inc/class_language.php in MyBB before 1.2.13 has unknown impact and attack vectors related to the $lang

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• mybb mybbup to 1.2.12 inclusive

Other highest-scoring records for the same primary product.

• CVE-2022-24734Remote code execution in mybb
  51Plan
• CVE-2018-17128A Persistent XSS issue was discovered in the Visual Editor in MyBB before 1.8.19 via a Video MyCode.
  43Plan
• CVE-2011-10018myBB 1.6.4 Backdoor Arbitrary Command Execution
  41Plan
• CVE-2017-16780The installer in MyBB before 1.8.13 allows remote attackers to execute arbitrary code by writing to the configuration file.
  41Plan
• CVE-2011-5133Unspecified vulnerability in MyBB before 1.6.5 has unknown impact and attack vectors, related to an "unparsed user avatar in the buddy list.
  41Plan
• CVE-2015-2786Unspecified vulnerability in MyBB (aka MyBulletinBoard) before 1.8.4 has unknown attack vectors related to "Group join request notifications
  40Plan

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const file = path.join(ROOT, req.query.name);2res.sendFile(file);

1const file = path.resolve(ROOT, req.query.name);2if (!file.startsWith(ROOT + path.sep)) {3  return res.sendStatus(400);4}5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.