CVE-2026-82726

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 77% 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
Elevated
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.3Exploit: Elevated riskExposed: 0

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

Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted Host header.

AshPhoenix.Helpers.get_subdomain/2 stripped the root domain with String.replace(host, ~r/.?#{root_host}/, ""). The root host was interpolated raw, so each . became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With root_host example.com, Host: foo.exampleXcom.attacker.net returned the tenant foo.attacker.net. A metacharacter-bearing or nil root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so TENANT.EXAMPLE.COM and EXAMPLE.COM slipped past the root-host allowlist. conn.host comes from the client Host header. The fix matches the root host case-insensitively and only as an exact trailing suffix.

This issue affects ash_phoenix: from 2.1.26 before 2.3.25.

CVSS v3
6.3
EG Score
6.3(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity63% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

August 31, 2026

Last Modified

September 1, 2026

Advisory Details (4)

Auto-updated Aug 31, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github_commit Patch Available

commit 8306f29e7752 (ash-project/ash_phoenix)

Patch available: ash-project/ash_phoenix v2.3.25 (contains commit 8306f29e7752)

https://github.com/ash-project/ash_phoenix/commit/8306f29e77526840c89f3cd244996ce7c0fa2cda
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-82726
generic

CVE-2026-82726

https://cna.erlef.org/cves/CVE-2026-82726.html
github Patch Available🟡 PoC Available

Improper neutralization in `AshPhoenix.Helpers.get_subdomain/2` in AshPhoenix lets a crafted Host header select the tenant or cause denial of service · Advisory · ash-project/ash_phoenix · GitHub

https://github.com/ash-project/ash_phoenix/security/advisories/GHSA-rpf8-q9jh-qxrr

Affected Packages

(1 across 1 ecosystem)
Hex(1)
PackageVulnerable rangeFixed inDependents
ash_phoenix2.1.26 ... 2.3.9 (27 versions)2.3.25—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 33× 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. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 08:23 UTCEG score recompute
  3. 2026-09-17 06:05 UTCEG score recompute
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-16 03:46 UTCEG score recompute
  7. 2026-09-15 03:12 UTCEPSS rescore
  8. 2026-09-15 03:12 UTCEPSS rescore
  9. 2026-09-13 23:11 UTCEG score recompute
  10. 2026-09-12 20:54 UTCEG score recompute
  11. 2026-09-11 18:36 UTCEG score recompute
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-10 16:18 UTCEG score recompute
  15. 2026-09-09 13:47 UTCEG score recompute
  16. 2026-09-08 22:01 UTCEPSS rescore
  17. 2026-09-07 08:51 UTCEG score recompute
  18. 2026-09-06 13:48 UTCEPSS rescore
  19. 2026-09-06 06:32 UTCEG score recompute
  20. 2026-09-05 15:31 UTCEPSS rescore
  21. 2026-09-05 04:14 UTCEG score recompute
  22. 2026-09-04 05:07 UTCEPSS rescore
  23. 2026-09-02 23:39 UTCEG score recompute
  24. 2026-09-02 14:12 UTCEPSS rescore
  25. 2026-09-01 17:44 UTCEG score recompute
Show 8 more
  1. 2026-09-01 13:54 UTCEPSS rescore
  2. 2026-09-01 04:40 UTCEPSS rescore
  3. 2026-09-01 04:40 UTCEPSS rescore
  4. 2026-08-31 15:25 UTCEG score recompute
  5. 2026-08-31 14:54 UTCEG score recompute
  6. 2026-08-31 04:27 UTCEG score recompute
  7. 2026-08-31 03:28 UTCEG score recompute
  8. 2026-08-31 03:27 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-82726?
CVE-2026-82726 is a medium vulnerability published on August 31, 2026. Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted Host header. AshPhoenix.Helpers.getsubdomain/2 stripped the root domain with String.replace(host, ~r/.?#{roothost}/,…
When was CVE-2026-82726 disclosed?
CVE-2026-82726 was first published in the National Vulnerability Database on August 31, 2026, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-82726 actively exploited?
CVE-2026-82726 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 77.0% of all scored CVEs.
What is the CVSS score of CVE-2026-82726?
CVE-2026-82726 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-82726?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-82726, 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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