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highPath Traversalpublic exploit

CVE-2026-103060

CVE-2026-103060 — Path traversal in rebar3 via unvalidated dependency app names

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in erlang rebar3 allows a malicious package publisher to delete a directory outside the project's _build directory and extract package files into it when a developer fetches dependencies. A package release's dependencies in a Hex registry carry an app field that names the dependency's OTP application. rebar3 uses this field as the dependency's name without validating it (rebar_packages:parse_deps/1) and builds the dependency's directory from that name (rebar_app_utils:dep_to_app/7). rebar_fetch:download_source_online/2 deletes that directory with rm -rf and moves the fetched package into it. hex.pm didn't restrict the field to a directory name before 2026-10-12, so a publisher could set it to a value such as ../../../../target. When a project depends on such a release directly or transitively, rebar3 get-deps deletes the directory the name resolves to and writes the dependency's files there. This happens before the dependency's own rebar.config.script is evaluated, and get-deps compiles nothing. This issue affects rebar3: from 3.7.0-rc1 before 3.27.2.

Published Updated Sources: NVD, erlang (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

0%

ahead of 0% of scored CVEs

Affects

erlang

2 products listed

CVSS base

7.5

high

Remediation

The vendor's own words where we have them.

Upgrade rebar3 to 3.27.2 or later, for example with rebar3 local upgrade. rebar3 then fails with an error when a dependency's name, including the app name a package release gives a dependency, isn't a letter followed by letters, digits, _ and -.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Prioritize based on EPSS, PoC availability, and external exposure.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
erlangrebar33.7.0-rc1 to < 3.27.2Vulnerable
erlangrebar356b7d88975aa8da6446857cfd92de0825024bf63Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Scope

X

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

A

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
7.5CVSS 4.0high——erlang (CNA)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

  • Execute Unauthorized Code or Commands
  • Modify Files or Directories
  • Read Files or Directories
  • DoS: Crash, Exit, or Restart

Mitigation: Assume all input is malicious. Use an accept known good input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, boat may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as red or blue. Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single . character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as / to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering / is insufficient protection if the filesystem also supports the use of as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if ../ sequences are removed from the .../...// string in a sequential fashion, two instances of ../ would be removed from the original string, but the remaining characters would still form the ../ string.

Weakness & attack patterns

  • CWE-22Path Traversal

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-126 · Path TraversalCAPEC-76 · Manipulating Web Input to File System CallsCAPEC-79 · Using Slashes in Alternate EncodingCAPEC-64 · Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-78 · Using Escaped Slashes in Alternate Encoding

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /1), /7), /2, /../../../target.
  • Prioritize edge telemetry for network-reachable rebar3.
  • Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.
web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026

  2. Added · CVSS 3.1 7.5 (AV:N)

    Oct 12, 2026 · NVD

  3. Initial · CVE published

    Oct 12, 2026 · NVD

  4. CVE published by MITRE.

    Oct 12, 2026 · SOCRadar CTI

References

5 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-103060 is Path traversal in rebar3 via unvalidated dependency app names, a high vulnerability affecting rebar3 from erlang. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-103060. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.5 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.