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.
Metrics
Affected Vendors & Products
No advisories yet.
Solution
No solution given by the vendor.
Workaround
On a multi-user host, set TMPDIR to a private per-user directory with mode 0700 before running Mix, so that System.tmp_dir/0 resolves to a location other users cannot pre-create or read. Alternatively, keep partitioned compilation disabled by leaving MIX_OS_DEPS_COMPILE_PARTITION_COUNT unset or at 1, which keeps the configuration inside the parent process.
Fri, 30 Oct 2026 09:15:00 +0000
| Type | Values Removed | Values 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. | |
| Title | Insecure temporary file in mix deps.partition lets a local user execute code in another user's dependency build | |
| First Time appeared |
Elixir-lang
Elixir-lang elixir |
|
| Weaknesses | CWE-377 | |
| CPEs | cpe:2.3:a:elixir-lang:elixir:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Elixir-lang
Elixir-lang elixir |
|
| References |
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|
| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-10-30T09:01:05.212Z
Reserved: 2026-10-14T21:45:01.541Z
Link: CVE-2026-97209
No data.
Status : Received
Published: 2026-10-30T09:17:15.640
Modified: 2026-10-30T09:17:15.640
Link: CVE-2026-97209
No data.
OpenCVE Enrichment
No data.