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NVD / CVE Program· CNA EEF

CVE-2026-21620: Relative Path Traversal, Improper Isolation or Compartmentalization vulnerability in erlang otp erlang/otp (tftp_file modules), erlang otp i

Noroxi assessment

Priority: Monitor (action score 9/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.51% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Erlang OTP 1.1.1.1, 1.2.2.1, 1.2.4; azl3 erlang 26.2.5.15-1 on Azure Linux 3.0 26.2.5.17-1; cbl2 erlang 25.3.2.21-5 on CBL Mariner 2.0 25.3.2.21-6.

Low priority for now. Upgrade to Erlang OTP 1.1.1.1, 1.2.2.1, 1.2.4; azl3 erlang 26.2.5.15-1 on Azure Linux 3.0 26.2.5.17-1; cbl2 erlang 25.3.2.21-5 on CBL Mariner 2.0 25.3.2.21-6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 2.3 · v4.0—No exploit Fix available
Published
Feb 20, 2026
Updated
Jul 24, 2026
EPSS
0.5% · 44th percentile

Report tools

JSON

Action score

9

Monitor

Low priority for now.

CVSS
9 / 40 · 2.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
2.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-21620

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • Erlang OTP

    • 17.0 and lateraffected · otpfixed in 26.2.5.17, 27.3.4.8, 28.3.2
    • 07b8f441ca711f9812fad9e9115bab3c3aa92f79 and lateraffected · gitfixed in 655fb95725ba2fb811740b57e106873833824344, 3970738f687325138eb75f798054fa8960ac354e, 696fdec922661d4a3cc528fc34bc24fae8d4ad8a
    • 5.10 and later · before 7.0affected · otp
    • 1.0 and lateraffected · otpfixed in 1.1.1.1, 1.2.2.1, 1.2.4

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12erlangbefore 1:25.2.3+dfsg-1+deb12u41:25.2.3+dfsg-1+deb12u4
Debian:13erlangbefore 1:27.3.4.1+dfsg-1+deb13u21:27.3.4.1+dfsg-1+deb13u2
Debian:14erlangbefore 1:27.3.4.8+dfsg-11:27.3.4.8+dfsg-1
openSUSE:Leap 16.0erlangbefore 27.1.3-160000.4.127.1.3-160000.4.1
openSUSE:Tumbleweederlang27before 27.1.3-2.127.1.3-2.1

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-89422TLS 1.3 client skips server authentication when ServerHello carries an unsolicited pre_shared_key extension
    37Monitor
  • CVE-2026-74835inets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body Reception
    34Monitor
  • CVE-2026-71380httpd applies no timeout while receiving a request body, parking a worker on a stalled client
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-48040Sep 11, 2025 · Malicious Key Exchange Messages may Lead to Excessive Resource Consumption
    27Monitor
  • ← EarlierCVE-2025-48041Sep 11, 2025 · SSH_FXP_OPENDIR may Lead to Exhaustion of File Handles
    28Monitor
  • Later →CVE-2026-47078Jul 27, 2026 · Relative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass
    19Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Erlang OTP1.1.1.1Vendor (CNA)
Erlang OTP1.2.2.1Vendor (CNA)
Erlang OTP1.2.4Vendor (CNA)
Erlang OTP26.2.5.17Vendor (CNA)
Erlang OTP27.3.4.8Vendor (CNA)
Erlang OTP28.3.2Vendor (CNA)
Erlang OTP3970738f687325138eb75f798054fa8960ac354eVendor (CNA)
Erlang OTP655fb95725ba2fb811740b57e106873833824344Vendor (CNA)
Erlang OTP696fdec922661d4a3cc528fc34bc24fae8d4ad8aVendor (CNA)
Erlang OTP7.0Vendor (CNA)
azl3 erlang 26.2.5.15-1 on Azure Linux 3.026.2.5.17-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 erlang 25.3.2.21-5 on CBL Mariner 2.025.3.2.21-6 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 erlang 25.3.2.21-5 on CBL-Mariner 2.025.3.2.21-6 · Release NotesMicrosoft (MSRC)
debian:erlang1:25.2.3+dfsg-1+deb12u4 · Debian:12Package registry (OSV)
opensuse:erlang27.1.3-160000.4.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:erlang2727.1.3-2.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-47078157 days apartRelative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass
    19Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-23 · Relative Path Traversal

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records