---
id: CVE-2026-55078
aliases:
  - GHSA-2mg2-p7r7-g27f
title: >-
  Coder: Zip upload decompression lacks aggregate size limit, enabling denial of
  service
summary: >-
  Coder: Zip upload decompression lacks aggregate size limit, enabling denial of
  service
severity: medium
cvss: 6.5
cwe:
  - CWE-409
  - CWE-770
vendor: coder
product: github.com/coder/coder/v2
ecosystem: go
affected:
  - 'github.com/coder/coder/v2 >= 2.34.0, < 2.34.2'
  - 'github.com/coder/coder/v2 >= 2.33.0, < 2.33.8'
  - 'github.com/coder/coder/v2 >= 2.30.0, < 2.32.7'
  - 'github.com/coder/coder/v2 >= 2.17.0, < 2.29.17'
patched:
  - github.com/coder/coder/v2 2.34.2
  - github.com/coder/coder/v2 2.33.8
  - github.com/coder/coder/v2 2.32.7
  - github.com/coder/coder/v2 2.29.17
published: '2026-07-06'
updated: '2026-07-06'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-2mg2-p7r7-g27f'
references:
  - url: 'https://github.com/coder/coder/security/advisories/GHSA-2mg2-p7r7-g27f'
  - url: 'https://github.com/coder/coder/pull/25877'
  - url: 'https://github.com/advisories/GHSA-2mg2-p7r7-g27f'
tags:
  - ghsa
  - go
ingestedAt: '2026-07-06T21:45:52.961Z'
epss: 0.00602
epssPercentile: 0.46482
---

## Overview

### Summary

`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.

> **Note:** Exploitation requires authenticated file-upload access and the impact is limited to availability (denial of service).

### Impact

An authenticated user could upload a zip within the 100 MiB upload limit but containing many highly compressible entries whose decompressed size exhausted memory, crashing `coderd` before any RBAC check. Repeated requests could keep the service unavailable. This is a denial of service; it does not allow data disclosure or code execution.

### Patches

The fix adds a metadata preflight check that sums projected entry sizes and a streaming writer that enforces the aggregate limit during decompression.

The fix was backported to all supported release lines:

| Release line | Patched version |
|---|---|
| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |
| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |
| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |
| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |

### Workarounds

Restrict file-upload permissions to trusted users or place a reverse proxy with request-body size limits in front of `coderd`.

### Resources

- Fix: #25877

### Credits

Coder would like to thank Anthropic's Security Team (ANT-2026-22438) for independently disclosing this issue!

## Affected packages

- `github.com/coder/coder/v2 >= 2.34.0, < 2.34.2`
- `github.com/coder/coder/v2 >= 2.33.0, < 2.33.8`
- `github.com/coder/coder/v2 >= 2.30.0, < 2.32.7`
- `github.com/coder/coder/v2 >= 2.17.0, < 2.29.17`

## Remediation

Upgrade to a patched release:

- `github.com/coder/coder/v2 2.34.2`
- `github.com/coder/coder/v2 2.33.8`
- `github.com/coder/coder/v2 2.32.7`
- `github.com/coder/coder/v2 2.29.17`