CVE-2026-97209
Insecure temporary file in mix deps.partition lets a local user execute code in another user's dependency build
Description
Insecure Temporary File vulnerability in Mix deps.partition in Elixir allows a local user to execute code as another user via a swapped partition config file. Partitioned dependency compilation passes the project configuration to each partition VM through a file in a fixed-name directory under the shared system temporary directory, and the partition trusts what it reads back. Another local user on the same host can exploit this during a mix deps.compile run that uses partitioned compilation. Mix.Tasks.Deps.Partition.server/4 in lib/mix/lib/mix/tasks/deps.partition.ex creates the directory with File.mkdir_p/1, which accepts an existing directory without checking its owner, so a user who created it first can replace the file before client/0 reads it. This issue affects mix: from 1.20.0-rc.4 before 1.20.5.
INFO
Published Date :
Oct. 30, 2026, 9:17 a.m.
Last Modified :
Oct. 30, 2026, 9:17 a.m.
Remotely Exploit :
No
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update Mix to version 1.20.5 or later.
- Ensure temporary directories are properly secured.
- Review dependency compilation processes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-97209.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-97209 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-97209
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-97209 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-97209 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Oct. 30, 2026
Action Type Old Value New Value Added Description Insecure Temporary File vulnerability in Mix deps.partition in Elixir allows a local user to execute code as another user via a swapped partition config file. Partitioned dependency compilation passes the project configuration to each partition VM through a file in a fixed-name directory under the shared system temporary directory, and the partition trusts what it reads back. Another local user on the same host can exploit this during a mix deps.compile run that uses partitioned compilation. Mix.Tasks.Deps.Partition.server/4 in lib/mix/lib/mix/tasks/deps.partition.ex creates the directory with File.mkdir_p/1, which accepts an existing directory without checking its owner, so a user who created it first can replace the file before client/0 reads it. This issue affects mix: from 1.20.0-rc.4 before 1.20.5. Added CVSS V4.0 AV:L/AC:L/AT:P/PR:L/UI:P/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:X Added CWE CWE-377 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/97xxx/CVE-2026-97209.json">CVE-2026-97209</a> Added Reference https://cna.erlef.org/cves/CVE-2026-97209.html Added Reference https://github.com/elixir-lang/elixir/commit/55eb91220a1de14dc5aa27029d1f45b0f5832b2d Added Reference https://github.com/elixir-lang/elixir/commit/7f3d95b60c28ae3026a5c1bf943166391245bfd1 Added Reference https://github.com/elixir-lang/elixir/commit/9adbe955c8664f4be77d879dd38c003dd39fa777 Added Reference https://github.com/elixir-lang/elixir/security/advisories/GHSA-96q6-xhwp-fc8q Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-97209