Coder up to 2.29.16/2.32.6/2.33.7/2.34.1 File Upload /api/v2/files CreateTarFromZip denial of service

Summaryinfo

A vulnerability was found in Coder up to 2.29.16/2.32.6/2.33.7/2.34.1. It has been declared as problematic. This issue affects the function CreateTarFromZip of the file /api/v2/files of the component File Upload Handler. Executing a manipulation can lead to denial of service. This vulnerability is tracked as CVE-2026-55078. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic was found in Coder up to 2.29.16/2.32.6/2.33.7/2.34.1. This vulnerability affects the function CreateTarFromZip of the file /api/v2/files of the component File Upload Handler. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

Coder allows organizations to provision remote development environments via Terraform. Starting in version 2.17.0 and prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `POST /api/v2/files` converts zip uploads to tar in memory via `CreateTarFromZip`, which enforced a per-entry size limit but no aggregate limit on total decompressed output, writing to an unbounded in-memory buffer. Exploitation requires authenticated file-upload access and the impact is limited to availability (denial of service). The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 adds a metadata preflight check that sums projected entry sizes and a streaming writer that enforces the aggregate limit during decompression. As a workaround, restrict file-upload permissions to trusted users or place a reverse proxy with request-body size limits in front of `coderd`.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-55078 since 06/16/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 2.29.17, 2.32.7, 2.33.8 or 2.34.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-42131). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Coder

Version

• 2.29.0
• 2.29.1
• 2.29.2
• 2.29.3
• 2.29.4
• 2.29.5
• 2.29.6
• 2.29.7
• 2.29.8
• 2.29.9
• 2.29.10
• 2.29.11
• 2.29.12
• 2.29.13
• 2.29.14
• 2.29.15
• 2.29.16
• 2.32.0
• 2.32.1
• 2.32.2
• 2.32.3
• 2.32.4
• 2.32.5
• 2.32.6
• 2.33.0
• 2.33.1
• 2.33.2
• 2.33.3
• 2.33.4
• 2.33.5
• 2.33.6
• 2.33.7
• 2.34.0
• 2.34.1

Website

• Product: https://github.com/coder/coder/

CPE 2.3info

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CPE 2.2info

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Once again VulDB remains the best source for vulnerability data.

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