Weakness Type (CWE)

CWE-23 — CWE-23 Relative Path Traversal

CAPEC

CVSS 4.0 Score

4.8

MEDIUM

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L

Vulnerability description

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 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to stdlib from 6.1 before 8.0.3, 7.3.0.1 and 6.2.2.4.

Affected

pkg:otp/stdlib

Module Source File Routine
zip src/zip.erl zip:unzip/1
zip:unzip/2
zip:extract/1
zip:extract/2
zip:check_dir_level/2
Status Type Version Changes / Fixed in
affected otp ⓘ 6.1
  • unaffected at 8.0.3
  • unaffected at 7.3.0.1
  • unaffected at 6.2.2.4

pkg:github/erlang/otp

Module Source File Routine
zip lib/stdlib/src/zip.erl zip:unzip/1
zip:unzip/2
zip:extract/1
zip:extract/2
zip:check_dir_level/2
Status Type Version Changes / Fixed in
affected otp ⓘ 27.1
affected git ⓘ 8d537f51a4 < 8a933c9c78

References

Credits

  • Finder: Jonatan Männchen
  • Finder: Zhang Delong
  • Remediation developer: John Högberg

CVE record as JSON:  GET /cves/CVE-2026-47078.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-47078.json