CVE-2026-55518

CRITICALPre-NVD 9.69.6
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.6 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
Elevated
9.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.6Exploit: NoneExposed: 0

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

Avo is a framework to create admin panels for Ruby on Rails apps. Prior to 3.32.1 and 4.0.0.beta.51, Avo's association attach workflow checks attach_? in the UI and GET /resources/:resource/:id/:related/new path, but the actual write endpoint, POST /resources/:resource/:id/:related, does not run the same authorization check before mutating the association through Avo::AssociationsController#create. An authenticated low-privileged Avo user can bypass hidden or disabled attach controls and directly attach related records to a parent record by sending a crafted POST request, which can lead to privilege escalation and cross-tenant data exposure where associations represent authorization-bearing relationships. This issue is fixed in versions 3.32.1 and 4.0.0.beta.51.

CVSS v3
9.6
EG Score
9.6(low)
EG Risk
—
EPSS
25.4%
KEV
Not listed

Published

June 17, 2026

Last Modified

July 20, 2026

Advisory Details (4)

Auto-updated Jul 17, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available🟡 PoC Available

Missing Authorization in Avo Association Attach Endpoint Allows Unauthorized Relationship Manipulation and Privilege Escalation · Advisory · avo-hq/avo · GitHub

https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg
github_release Patch Available

Release v3.32.1

Patch available: avo-hq/avo v3.32.1

https://github.com/avo-hq/avo/releases/tag/v3.32.1
github_pr Patch Available

fix: enforce attach authorization on association create (GHSA-8fq9-273g-6mrg)

Patch available: avo-hq/avo v3.32.1 (PR #4568 merged 2026-06-13)

https://github.com/avo-hq/avo/pull/4568
github_commit Patch Available

commit 995928e586fd (avo-hq/avo)

Patch available: avo-hq/avo v3.32.1 (contains commit 995928e586fd)

https://github.com/avo-hq/avo/commit/995928e586fd1788dd496bd51c4dbe4a79cb2b9c

Vendor Advisories for CVE-2026-55518(1)

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

Affected Packages

(1 across 1 ecosystem)
RubyGems(1)
PackageVulnerable rangeFixed inDependents
avo4.0.0.beta.1 ... 4.0.0.beta.9 (50 versions)4.0.0.beta.51—

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 6× 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. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:25 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 02:29 UTCEPSS rescore
  7. 2026-06-17 19:06 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-55518?
CVE-2026-55518 is a critical vulnerability published on June 17, 2026. Avo is a framework to create admin panels for Ruby on Rails apps. Prior to 3.32.1 and 4.0.0.beta.51, Avo's association attach workflow checks attach_<association>? in the UI and GET /resources/:resource/:id/:related/new path, but the actual write endpoint, POST /resources/:resource/:id/:related,…
When was CVE-2026-55518 disclosed?
CVE-2026-55518 was first published in the National Vulnerability Database on June 17, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55518 actively exploited?
CVE-2026-55518 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55518?
CVE-2026-55518 has a CVSS v3 base score of 9.6 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-55518?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55518, 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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