Bolt CMS up to 3.7.0 .sessions displayname code injection

Summaryinfo

A vulnerability was found in Bolt CMS up to 3.7.0. It has been declared as critical. This issue affects some unknown processing of the file /async/browse/cache/.sessions. Executing a manipulation of the argument displayname can lead to code injection. This vulnerability only affects products that are no longer supported by the maintainer. The identification of this vulnerability is CVE-2025-34086. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Bolt CMS up to 3.7.0 and classified as critical. This vulnerability affects some unknown processing of the file /async/browse/cache/.sessions. The manipulation of the argument displayname with an unknown input leads to a code injection vulnerability. The CWE definition for the vulnerability is CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Bolt CMS versions 3.7.0 and earlier contain a chain of vulnerabilities that together allow an authenticated user to achieve remote code execution. A user with valid credentials can inject arbitrary PHP code into the displayname field of the user profile, which is rendered unsanitized in backend templates. The attacker can then list and rename cached session files via the /async/browse/cache/.sessions and /async/folder/rename endpoints. By renaming a .session file to a path under the publicly accessible /files/ directory with a .php extension, the attacker can turn the injected code into an executable web shell. Finally, the attacker triggers the payload via a crafted HTTP GET request to the rogue file. NOTE: The vendor announced that Bolt 3 reached end-of-life after 31 December 2021.

The weakness was shared by Sivanesh Ashok. The advisory is shared for download at github.com. This vulnerability was named CVE-2025-34086 since 04/15/2025. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/16/2025). The MITRE ATT&CK project declares the attack technique as T1059.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-19905). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Content Management System

Vendor

• Bolt

Name

• CMS

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7.0

Support

• end of life

CPE 2.3info

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CPE 2.2info

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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