CVE-2026-53951Public exploit

Command execution via unnormalized trusted-prefix traversal

Published Jul 8, 2026 · Updated Jul 8, 2026

Path traversal in Copier 9.5.0 through 9.15.1 allows context-dependent attackers to execute commands through a crafted template URL. The trust check in copier/_settings.py applies raw string prefix matching without resolving dot segments, although the fetch path is normalized. Exploitation requires a configured trailing-slash trusted prefix and a user to update an attacker-controlled project, after which template tasks, migrations, or Jinja extensions run without the trust prompt.

CVSS severity8.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Copier 9.5.0 through 9.15.1 allows context-dependent attackers to execute commands through a crafted template URL. The trust check in copier/_settings.py applies raw string prefix matching without resolving dot segments, although the fetch path is normalized. Exploitation requires a configured trailing-slash trusted prefix and a user to update an attacker-controlled project, after which template tasks, migrations, or Jinja extensions run without the trust prompt.

The record

CVE
CVE-2026-53951
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
copier-org
Product
Copier
Classifications
CWE-94, CWE-22, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 9.5.0, < 9.15.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

copier-org · Copierversion=>= 9.5.0, < 9.15.2

Published CVSS scores

8.8GitHubCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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