CVE-2026-55428

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 67% of all CVEs by exploit prediction. 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: epss, secondary
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0

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

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the tailnet coordinator validates that an agent's Addresses derive from its authenticated UUID but applies no equivalent check to AllowedIPs. The coordinator forwards agent-supplied AllowedIPs verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each AllowedIPs prefix against the authenticating agent's UUID just like Addresses. As a workaround, monitor coordinator logs for agents advertising unexpected AllowedIPs prefixes.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
16.0%
KEV
Not listed

Published

July 6, 2026

Last Modified

July 8, 2026

Advisory Details (6)

Auto-updated Jul 8, 2026
Patch available. Sources: github_pr, github_release, github.
github Patch Available

Agent-supplied AllowedIPs not validated by tailnet coordinator allows route hijacking · Advisory · coder/coder · GitHub

https://github.com/coder/coder/security/advisories/GHSA-wrq8-fcv5-8hvp
github_release Patch Available

v2.34.2 [SECURITY]

Patch available: coder/coder v2.34.2

https://github.com/coder/coder/releases/tag/v2.34.2
github_release Patch Available

v2.33.8 [SECURITY]

Patch available: coder/coder v2.33.8

https://github.com/coder/coder/releases/tag/v2.33.8
github_release Patch Available

v2.32.7 [SECURITY]

Patch available: coder/coder v2.32.7

https://github.com/coder/coder/releases/tag/v2.32.7
github_release Patch Available

v2.29.17 [SECURITY]

Patch available: coder/coder v2.29.17

https://github.com/coder/coder/releases/tag/v2.29.17
github_pr

fix: validate agent-supplied AllowedIPs in coordinator

Fix merged in coder/coder PR #26144 on 2026-06-11 — awaiting tagged release

https://github.com/coder/coder/pull/26144

Vendor Advisories for CVE-2026-55428(1)

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

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/coder/coder———
github.com/coder/coder/v2—2.34.2—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 27× 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. 2026-07-25 14:18 UTCEPSS rescore
  2. 2026-07-24 14:18 UTCEPSS rescore
  3. 2026-07-23 14:18 UTCEPSS rescore
  4. 2026-07-23 03:20 UTCEG score recompute
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:25 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-19 02:29 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-16 17:03 UTCEPSS rescore
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 02:00 UTCEPSS rescore
  16. 2026-07-15 02:00 UTCEPSS rescore
  17. 2026-07-13 22:31 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 15:16 UTCEPSS rescore
Show 2 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-06 21:35 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55428?
CVE-2026-55428 is a high vulnerability published on July 6, 2026. Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the tailnet coordinator validates that an agent's Addresses derive from its authenticated UUID but applies no equivalent check to AllowedIPs. The coordinator…
When was CVE-2026-55428 disclosed?
CVE-2026-55428 was first published in the National Vulnerability Database on July 6, 2026, with the most recent update on July 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55428 actively exploited?
CVE-2026-55428 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 16.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55428?
CVE-2026-55428 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-55428?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55428, 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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