CVE-2026-55078: coder DoS — Fix

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`.

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CVSS v3.1 Score

6.5

MEDIUM

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

EPSS — Exploit Prediction

0.0060

Probability of exploitation

0.45%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-409 CWE-409

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
coder	coder	2.17.0 — 2.29.17
coder	coder	2.30.0 — 2.32.7
coder	coder	2.33.0 — 2.33.8
coder	coder	2.34.0 — 2.34.2

References

Advisories & Patches

https://github.com/coder/coder/pull/25877 https://github.com/coder/coder/security/advisories/GHSA-2mg2-p7r7-g27f

Other References

https://github.com/coder/coder/releases/tag/v2.29.17 https://github.com/coder/coder/releases/tag/v2.32.7 https://github.com/coder/coder/releases/tag/v2.33.8 https://github.com/coder/coder/releases/tag/v2.34.2

Frequently Asked Questions

What is CVE-2026-55078? +

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`. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-55078? +

CVE-2026-55078 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0060, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-55078? +

CVE-2026-55078 affects products from coder, specifically: coder. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-55078? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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