Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-55078: 0.60% estimated exploitation activity in the next 30 days; percentile 48.85 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 | | 2.33 | v2.33.8 | | 2.32 |…

Published by the source

6 Jul 2026, 21:06 UTC

Last modified by the source

6 Jul 2026, 21:06 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2mg2-p7r7-g27f

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-55078

Advisory: Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service
IDs: CVE-2026-55078, GHSA-2mg2-p7r7-g27f
Record: https://patchnext.com/advisories/cve-2026-55078 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/coder/coder/v2 2.34.2, 2.33.8, 2.32.7, 2.29.17. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/coder/coder/v2: affected >= 2.34.0, < 2.34.2; >= 2.33.0, < 2.33.8; >= 2.30.0, < 2.32.7; >= 2.17.0, < 2.29.17; fixed in 2.33.8, 2.29.17, 2.34.2, 2.32.7

## Suggested inspection (read-only)
- Go github.com/coder/coder/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/coder/coder/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2mg2-p7r7-g27f (GitHub-reviewed advisory GHSA-2mg2-p7r7-g27f lists affected ranges: Go github.com/coder/coder/v2 >=2.34.0 =2.33.0 =2.30.0 =2.17.0 <2.29.17)

Commands are suggestions: review each one before running it.