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Vulnerability · Published Oct 30, 2026 · Assigned by EEF

CVE-2026-97209Insecure temporary file in mix deps.partition lets a local user execute code in another user's dependency build

Medium 5.4

In plain English

A medium-severity security flaw in elixir from elixir-lang. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).

Severity (CVSS 4.0)5.4Medium
Exploit odds (30 days)0.1%top 98.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:14elixir-langno fix listedDEBIAN-CVE-2026-97209

Affected products (as reported)

VendorProductVersions
elixir-lang elixir 1.20.0-rc.4 – before 1.20.5
elixir-lang elixir 7f3d95b60c28ae3026a5c1bf943166391245bfd1 – before *

Weakness: CWE-377 · Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References