CVE-2026-9495

HIGHNVD 7.37.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 7.3 from GitHub Security Advisory published 2026-05-26. NVD baseline CVSS 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated
7.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.3Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Versions of the package @koa/router from 14.0.0 and before 15.0.0 are vulnerable to Access Control Bypass due to the middleware being silently dropped from the execution chain when the router prefix contains path parameters. Depending on what the skipped middleware was supposed to protect, an attacker could bypass authentication and authorization, evade rate limiting or bypass input sanitization.

CVSS v3
7.3
EG Score
7.3HIGHmedium confidence
EG Risk
64
EG Risk 64/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity73% × 45%
Impact severity (EG Severity): CVSS 7.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
48th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.3): severity, escalated by confirmed exploitation. This CVE's 7.3 is its impact severity (EG Severity), not escalated.

EG Severity
7.3 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-18). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 26, 2026

Last Modified

July 23, 2026

Advisory Details (3)

Auto-updated Jun 9, 2026
Patch available. Sources: github_pr.
GitHub pull request

Fix: Ensure .use() middleware works when path or prefix contains parameters

Upstream fix in progress (PR #206 · koajs/router, state=closed)

https://github.com/koajs/router/pull/206
Web page

Access Control Bypass in @koa/router | CVE-2026-9495 | Snyk

https://security.snyk.io/vuln/SNYK-JS-KOAROUTER-12215044
Web page

[fix] Router middleware not applied when prefix contains path parameters (v14.0.0 regression) · Issue #202 · koajs/router · GitHub

https://github.com/koajs/router/issues/202

Vendor Advisories for CVE-2026-9495(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)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
@koa/router—
  • 14.0.0 up to 15.0.0: fixed in 15.0.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 37× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 216 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 117 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-10-19 13:52 UTCEG score recompute
  3. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
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  5. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
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  9. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
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  15. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.6% · 47th percentile
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  1. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-09-30 02:39 UTCOSV refresh
  4. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 47th percentile
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  8. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  9. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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  22. 2026-09-11 03:23 UTCOSV refresh
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  37. 2026-08-24 14:18 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  38. 2026-08-23 16:25 UTCEG score recompute
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  40. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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  74. 2026-08-02 04:15 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-9495?
CVE-2026-9495 is a high-severity vulnerability; its CVE record was published on May 26, 2026. Versions of the package @koa/router from 14.0.0 and before 15.0.0 are vulnerable to Access Control Bypass due to the middleware being silently dropped from the execution chain when the router prefix contains path parameters. Depending on what the skipped middleware was supposed to protect, an…
When was the CVE record for CVE-2026-9495 published?
The CVE record for CVE-2026-9495 was published on May 26, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 23, 2026; the record at its source may have been updated since.
Is CVE-2026-9495 actively exploited?
CVE-2026-9495 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (48th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-9495?
CVE-2026-9495 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2026-9495?
A fix for CVE-2026-9495 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-9495 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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