Path traversal in rebar3 via unvalidated dependency app names (CVE-2026-103060)
Published Last modified Sources: CVE.org, OSV
What is affected, what to do
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.
Update Erlang Rebar3 to version 3.27.2.
- Affected
- Erlang Rebar3
lt 3.7.0-rc1..3.27.2
- Erlang Rebar3
- Fixed in
- Erlang Rebar3
3.27.2
- Erlang Rebar3
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Metrics
7.5
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v4
7.5
CVSS v4
Severity High on the scale from 0 to 10.
Source: CVE.org, OSV
0.4 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 39.1
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 79.72 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.5 Methodology
CVSS v4
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.5
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.4 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 39.1
- High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: proof of concept · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 16 October 2026
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-22
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
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.
Source: cvelistv5, NVD (NIST), OSV (Open Source Vulnerabilities)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| erlang | rebar3 |
|
|
Vendors and products
Weakness classes (CWE)
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Base
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Entry at MITRE CWE-22
References & sources
- github.comGitHub Advisoryrelated, Vendor advisory
- cna.erlef.orgEEF CNA record for CVE-2026-103060related
- OSV (Open Source Vulnerabilities)OSV record EEF-CVE-2026-103060related
- github.comIntroducing commit 56b7d88 in erlang/rebar3related
- github.comFix commit e35282b in erlang/rebar3Patch
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: proof of concept, automatable: no
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://github.com/erlang/rebar3/security/advisories/GHSA-6ggr-r7mh-2mv8SSVC assessment added —{"id":"CVE-2026-103060","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T17:43:00.338501Z"}Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0
ReceivedEEF
CVSS V4.0: AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness type: CWE-22
Description added or changed
New references:- https://cna.erlef.org/cves/CVE-2026-103060.html
- https://github.com/erlang/rebar3/commit/56b7d88975aa8da6446857cfd92de0825024bf63
- https://github.com/erlang/rebar3/commit/e35282b26e499b1d9e8f30bba9dccd71cd8b02ba
- https://github.com/erlang/rebar3/security/advisories/GHSA-6ggr-r7mh-2mv8
and 1 more reference
Show 9 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —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.CVSS added —AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/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:XWeakness type (CWE) added —CWE-22Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/103xxx/CVE-2026-103060.json">CVE-2026-103060</a>Reference added —https://cna.erlef.org/cves/CVE-2026-103060.htmlReference added —https://github.com/erlang/rebar3/commit/56b7d88975aa8da6446857cfd92de0825024bf63Reference added —https://github.com/erlang/rebar3/commit/e35282b26e499b1d9e8f30bba9dccd71cd8b02baReference added —https://github.com/erlang/rebar3/security/advisories/GHSA-6ggr-r7mh-2mv8Reference added —https://osv.dev/vulnerability/EEF-CVE-2026-103060Source identifier: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
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