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CVE-2025-55214VulnerabilityPublished

CVE-2025-55214: copier · Path Traversal

Affects copierSource CVE Database V5

0

Not known to be exploited · CVSS 6.9 Medium · fixed in 9.9.1 : update copier when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 9.9.1
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

AI-suggested

1. Upgrade Copier to version 9.9.1 or later immediately to apply the official patch that fixes this path traversal vulnerability. 2. Implement strict validation and vetting of all templates before use, especially those sourced externally or from third parties. 3. Restrict Copier usage to trusted users and environments, minimizing exposure to untrusted templates. 4. Employ filesystem monitoring tools to detect unexpected file writes or modifications outside designated project directories during template rendering. 5. Integrate template scanning tools or static analysis to detect suspicious path traversal patterns in templates before execution. 6. Use containerized or sandboxed environments for template rendering to limit the impact of potential file overwrites. 7. Educate developers and DevOps teams about the risks of using untrusted templates and the importance of applying the --UNSAFE or --trust flags only when absolutely necessary and with caution.

Description

Copier library and CLI app for rendering project templates. From 7.1.0 to before 9.9.1, 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 write files outside the destination path where a project shall be generated or updated. This is possible when rendering a generated directory structure whose rendered path is either a relative parent path or an absolute path. Constructing such paths is possible using Copier's builtin pathjoin Jinja filter and its builtin _copier_conf.sep variable, which is the platform-native path separator. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. This vulnerability is fixed in 9.9.1.

References

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