CVE-2026-55429

HIGHPre-NVD 8.78.7
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.7 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
8.7
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: —CVSS: 8.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Coder's workspace app upsert allows cross-workspace agent rebinding via user-controlled app ID

Summary

UpsertWorkspaceApp overwrites an existing app's agent_id on a primary-key conflict and insertAgentApp accepts the app ID from the provisioner's CompleteJob payload without verifying it belongs to the workspace being built. CompleteJob runs under dbauthz.AsProvisionerd so the authorization layer does not block the cross-workspace upsert.

> Note: Exploitation requires elevated access as a template author or external provisioner operator.

Impact

A user with template authorship or external provisioner access can submit a CompleteJob payload with a known victim app UUID and an attacker-controlled agent ID. On completion of the attacker's build the victim's app row is rebound to the attacker's agent so later app traffic such as IDE and terminal sessions is proxied to the attacker's workspace. App UUIDs are discoverable through the public API.

Patches

The fix verifies that any existing workspace_apps row matching the supplied ID belongs to the workspace being built and rejects cross-workspace agent reassignment.

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 | v2.32.7 | | 2.29 (ESR) | v2.29.17 |

Workarounds

None. Upgrading is required.

Resources

  • Fix: #26103

Credits

Coder would like to thank Anthropic's Security Team (ANT-2026-22441) for independently disclosing this issue!

CVSS v3
8.7
EG Score
8.7(low)
EPSS
—
KEV
Not listed

Published

July 6, 2026

Last Modified

July 6, 2026

Vendor Advisories for CVE-2026-55429(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 1× in last 7d / 1× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 21:35 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-55429?
CVE-2026-55429 is a high vulnerability published on July 6, 2026. Coder's workspace app upsert allows cross-workspace agent rebinding via user-controlled app ID Summary UpsertWorkspaceApp overwrites an existing app's agent_id on a primary-key conflict and insertAgentApp accepts the app ID from the provisioner's CompleteJob payload without verifying it belongs to…
When was CVE-2026-55429 disclosed?
CVE-2026-55429 was first published in the National Vulnerability Database on July 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-55429?
CVE-2026-55429 has a CVSS v4.0 base score of 8.7 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-55429?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55429, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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