TFTP Path Traversal
## Summary Relative Path Traversal, Improper Isolation or Compartmentalization vulnerability in erlang otp erlang/otp (tftp\_file modules), erlang otp inets (tftp\_file modules), erlang otp tftp (tftp\_file modules) allows Relative Path Traversal. This vulnerability is associated with program files lib/tftp/src/tftp\_file.erl, src/tftp\_file.erl. This issue affects OTP from OTP 17.0 before OTP 28.3.2, OTP 27.3.4.8 and OTP 26.2.5.17, corresponding to tftp from 1.0 before 1.2.4, 1.2.2.1 and 1.1.1.1; also inets from 5.10 before 7.0. ## Configuration A TFTP server must be started and the TFTP port must be reachable by the attacker, using the tftp application (or the legacy inets TFTP service) with the tftp\_file callback module configured with the {root\_dir, Dir} option.
02 / AFFECTED SOFTWARE
Affected packages
87 explicit affected versions
81 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
## Summary Relative Path Traversal, Improper Isolation or Compartmentalization vulnerability in erlang otp erlang/otp (tftp\_file modules), erlang otp inets (tftp\_file modules), erlang otp tftp (tftp\_file modules) allows Relative Path Traversal. This vulnerability is associated with program files lib/tftp/src/tftp\_file.erl, src/tftp\_file.erl. This issue affects OTP from OTP 17.0 before OTP 28.3.2, OTP 27.3.4.8 and OTP 26.2.5.17, corresponding to tftp from 1.0 before 1.2.4, 1.2.2.1 and 1.1.1.1; also inets from 5.10 before 7.0. ## Configuration A TFTP server must be started and the TFTP port must be reachable by the attacker, using the tftp application (or the legacy inets TFTP service) with the tftp\_file callback module configured with the {root\_dir, Dir} option.
Relative Path Traversal, Improper Isolation or Compartmentalization vulnerability in erlang otp erlang/otp (tftp_file modules), erlang otp inets (tftp_file modules), erlang otp tftp (tftp_file modules) allows Relative Path Traversal. This vulnerability is associated with program files lib/tftp/src/tftp_file.erl, src/tftp_file.erl. This issue affects OTP from OTP 17.0 before OTP 28.3.2, OTP 27.3.4.8 and OTP 26.2.5.17, corresponding to tftp from 1.0 before 1.2.4, 1.2.2.1 and 1.1.1.1; also inets from 5.10 before 7.0.
05 / REFERENCES
Further evidence
- https://cna.erlef.org/cves/CVE-2026-21620.html
- https://github.com/erlang/otp/commit/3970738f687325138eb75f798054fa8960ac354e
- https://github.com/erlang/otp/commit/655fb95725ba2fb811740b57e106873833824344
- https://github.com/erlang/otp/commit/696fdec922661d4a3cc528fc34bc24fae8d4ad8a
- https://github.com/erlang/otp/pull/10706
- https://github.com/erlang/otp/security/advisories/GHSA-hmrc-prh3-rpvp
- https://www.erlang.org/doc/system/versions.html#order-of-versions
- https://github.com
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21620.json
- https://github.com/erlang/otp
- https://nvd.nist.gov/vuln/detail/CVE-2026-21620
- https://osv.dev/vulnerability/EEF-CVE-2026-21620