What’s Vulnerable › Vulnerabilities

CVE-2026-21620: TFTP Path Traversal

• Severity: low (CVSS 2.3 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-20 · updated 2026-07-24
• Weakness: CWE-23

Description

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.

Affected products

• Erlang OTP: from 17.0; from 5.10 before 7.0; from 1.0 — fixed in 7.0

How to fix

Upgrade to a fixed version: Erlang OTP 7.0. Check the vendor advisory for mitigations.

References

• 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://osv.dev/vulnerability/EEF-CVE-2026-21620
• https://www.erlang.org/doc/system/versions.html#order-of-versions

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