zopefoundation RestrictedPython up to 8.3 String Formatter string.Formatter.format privileges management

Summaryinfo

A vulnerability was found in zopefoundation RestrictedPython up to 8.3. It has been rated as problematic. The impacted element is the function string.Formatter.format of the component String Formatter. Performing a manipulation results in privileges management. This vulnerability is identified as CVE-2026-76825. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in zopefoundation RestrictedPython up to 8.3. It has been classified as problematic. This affects the function string.Formatter.format of the component String Formatter. The manipulation with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

RestrictedPython is a tool that helps define a subset of the Python language for accepting program input in a trusted environment. Prior to 8.4, RestrictedPython could allow a sandbox escape when a custom import policy or globals exposed the standard library string module, the string.Formatter class, a Formatter instance, or a Formatter subclass to restricted code. The string.Formatter methods format, get_field, get_value, and vformat performed attribute and item traversal internally without passing through RestrictedPython's safer_getattr protections. Restricted code could use those live object references to reach function globals, builtins, file access, or code execution primitives, affecting confidentiality, integrity, and availability in the host environment. This issue is fixed in version 8.4.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-76825 since 08/19/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The exploitation needs additional levels of successful authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 8.4 eliminates this vulnerability.

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Productinfo

Type

• Application Server Software

Vendor

• zopefoundation

Name

• RestrictedPython

Version

• 8.0
• 8.1
• 8.2
• 8.3

Website

• Product: https://github.com/zopefoundation/RestrictedPython/

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