CVE-2026-23968VulnerabilityPublished 21 Jan 2026

CVE-2026-23968: copier · UNIX Symbolic Link (Symlink) Following

Affects copierSource CVE Database V5

Not known to be exploited · CVSS 6.8 Medium : upgrade to 9.11.2 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

6.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 9.11.2

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

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade copier to 9.11.2.

Affected software

Product	Affected	Fixed in
copier-orgcopier	Affected <9.11.2	Fixed in 9.11.2
PyPIcopier`pkg:pypi/copier`Other threats	Affected <9.11.2	Fixed in 9.11.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade Copier to version 9.11.2 or later to benefit from the patched symlink handling. Until upgrade, explicitly set `_preserve_symlinks: true` in Copier configuration to prevent symlink resolution outside the template directory. Validate and audit all templates, especially those sourced externally, to ensure they do not contain malicious symlinks. Incorporate template rendering into secure CI/CD pipelines with strict access controls and sandboxing to limit file system exposure. Monitor for unusual file access or modifications during template generation. Educate developers and DevOps teams about the risks of symlink following and safe template usage. Consider implementing file system permissions and containerization to isolate template rendering processes. Regularly review Copier usage and dependencies to detect outdated versions.

Description

CVE-2026-23968 is a medium severity vulnerability in the Copier library and CLI tool used for rendering project templates. Versions prior to 9.11.2 allow safe templates to include arbitrary files or directories outside the intended template location by exploiting symbolic link (symlink) following behavior combined with the default setting `_preserve_symlinks: false`. This can lead to unintended file disclosure or manipulation during template generation. The vulnerability does not require privileges or authentication but does require user interaction to trigger template rendering. The issue is patched in version 9.11.2. European organizations using Copier versions before 9.

Impact

For European organizations, this vulnerability can lead to unauthorized disclosure or modification of sensitive files during automated project template rendering, potentially exposing confidential information or corrupting critical configuration files. Organizations using Copier in software development, DevOps pipelines, or automation tools are at risk, especially if templates are sourced from external or untrusted repositories. The impact is heightened in environments where templates are rendered with minimal oversight or where symlink preservation is not explicitly managed. This could result in data leaks, supply chain compromise, or disruption of development workflows. Confidentiality is primarily impacted, with some risk to integrity. Availability impact is minimal. The vulnerability’s exploitation requires user interaction (template rendering), so automated or unattended environments are particularly vulnerable if they process untrusted templates.

CWE-61UNIX Symbolic Link (Symlink) Following (opens in a new tab)
Compound weaknessLikelihood of exploit: HighOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.
Implementation
Symbolic link attacks often occur when a program creates a tmp directory that stores files/links. Access to the directory should be restricted to the program as to prevent attackers from manipulating the files.
Architecture and Design · Separation of Privilege
Follow the principle of least privilege when assigning access rights to entities in a software system.
OWASP Cheat Sheets
Authorization (opens in a new tab)
Attack patterns
Leveraging Race Conditions via Symbolic Links (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jan 2026, 08:48 UTC

WeaknessesCWE-61

Technical details

References

Community reviews

Related threats