6.8

CVE-2026-55438: coder Origin Validation Error

CVSS: 6.8v3.1MediumAnalyzed
AliasesGHSA-5wg6-jmq2-53pwGO-2026-5918
Published 08-07-2026Last modified 08-07-2026
Open JSON

Vulnerability summary

CVE-2026-55438 is a medium (CVSS 6.8) Origin Validation Error vulnerability in coder. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12% of scored vulnerabilities.

Overall risk
27/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.8/10
010
Medium · v3.1 (NVD)
EPSS score
0.22%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:21483-1

Timeline

  1. 08-07-2026
    PublishedVulnerability first disclosed.
  2. 08-07-2026
    Last modifiedVulnerability information updated.

Description

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

0.00 pp

From 0.22% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.22%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Coder1 product
  • coder< 2.29.17 | ≥ 2.30.0, < 2.32.7 | ≥ 2.33.0, < 2.33.8 | ≥ 2.34.0, < 2.34.2
Github.com/coder1 product
  • coderAll versions (No fix recorded)
Github.com/coder/coder1 product
  • v2≥ 2.33.0, < 2.33.8 | ≥ 2.30.0, < 2.32.7 | < 2.29.17 | ≥ 2.34.0, < 2.34.2

3 vendors · 3 products

References

8 links