Relative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass
## Summary Relative Path Traversal vulnerability in Erlang OTP (stdlib zip module) allows writing files outside the intended extraction directory via a crafted zip archive. `zip:unzip/1,2` and `zip:extract/1,2` validate entry paths using `zip:check_dir_level/2`, which tracks directory depth as a running integer counter: `..` decrements it, normal path components increment it. The caller rejects only paths where the final counter value is less than zero. A path such as `../x/y` causes the counter to go negative mid-traversal then recover to zero, passing validation while resolving to a location outside the extraction directory when joined with the current working directory via `add_cwd`. This vulnerability is associated with program file `lib/stdlib/src/zip.erl`. This issue affects OTP from OTP 27.1 before OTP 27.3.4.15, OTP 28.5.0.4, and OTP 29.0.4, corresponding to stdlib from 6.1 before 6.2.2.4, 7.3.0.1, and 8.0.3.
EEF-CVE-2026-47078
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:EEF-CVE-2026-47078
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"repo": "https://github.com/erlang/otp",
"type": "GIT",
"events": [
{
"introduced": "8d537f51a4262d24f3395c4148323eaca9facbbd"
},
{
"fixed": "8a933c9c7835b06776d31d17b79b7336627d887a"
}
]
}
],
"database_specific": {
"source": "https://cna.erlef.org/osv/EEF-CVE-2026-47078.json"
}
}
]- Related CVEs
- CVE-2026-47078
Source reference:
/aliases
Publisher severity
No explicit severity was provided.
- Event
- #14311 · Revision 1
- Added to Heist Feed
- Publisher date