CVE-2026-55078: Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-07 · updated 2026-07-08
Weakness: CWE-409

Description

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`.

Affected products

coder: from 2.17.0 before 2.29.17; from 2.30.0 before 2.32.7; from 2.33.0 before 2.33.8; from 2.34.0 before 2.34.2 — fixed in 2.29.17, 2.32.7, 2.33.8, 2.34.2

How to fix

Upgrade to a fixed version: coder 2.29.17, 2.32.7, 2.33.8, 2.34.2. Check the vendor advisory for mitigations.

References

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