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CVE-2026-21620VulnerabilityPublished Updated

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

Affects erlangSource GCVE Database

0
Authoritative record:CVE-2026-21620· Low 2.3

Not known to be exploited · CVSS 2.3 Low · fixed in 1:16.b.3-dfsg-1ubuntu2.2+esm3 : update erlang when convenient.

Data as of 28 Oct 2026, 22:28 UTC

CVSS 4.0 base score
2.3Low
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 1:16.b.3-dfsg-1ubuntu2.2+esm3, 1:18.3-dfsg-1ubuntu3.1+esm4, 1:20.2.2+dfsg-1ubuntu2+esm4 +4
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSerlangpkg:deb/ubuntu/erlang?arch=source&distro=resoluteOther threatsAffected
  • <1:27.3.4.6+dfsg-1ubuntu0.2
Fixed in
  • 1:27.3.4.6+dfsg-1ubuntu0.2
Ubuntu 25.10erlangpkg:deb/ubuntu/erlang?arch=source&distro=questingOther threatsAffected
  • 1:27.3.4.1+dfsg-1 – 1:27.3+dfsg-1ubuntu1.1
5 affected builds
Fixed in–
Ubuntu 24.04 LTSerlangpkg:deb/ubuntu/erlang?arch=source&distro=nobleOther threatsAffected
  • <1:25.3.2.8+dfsg-1ubuntu4.8
Fixed in
  • 1:25.3.2.8+dfsg-1ubuntu4.8
Ubuntu 22.04 LTSerlangpkg:deb/ubuntu/erlang?arch=source&distro=jammyOther threatsAffected
  • <1:24.2.1+dfsg-1ubuntu0.8
  • =1:24.2+dfsg-1
Fixed in
  • 1:24.2.1+dfsg-1ubuntu0.8
Ubuntu Pro 20.04 LTSerlangpkg:deb/ubuntu/erlang?arch=source&distro=esm-infra/focalOther threatsAffected
  • <1:22.2.7+dfsg-1ubuntu0.5+esm3
  • =1:22.2+dfsg-1
Fixed in
  • 1:22.2.7+dfsg-1ubuntu0.5+esm3
Ubuntu Pro 18.04 LTSerlangpkg:deb/ubuntu/erlang?arch=source&distro=esm-infra/bionicOther threatsAffected
  • <1:20.2.2+dfsg-1ubuntu2+esm4
Fixed in
  • 1:20.2.2+dfsg-1ubuntu2+esm4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

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.

References

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