esm.sh is a no-build content delivery network (CDN) for web development. Prior to server version 137_7, the documented web.NewHandler static file server in web/handler.go joins the URL-decoded r.URL.Path with Config.AppDir without verifying that the result remains inside the configured application directory. URL-encoded dot segments such as %2e%2e bypass the plain traversal redirect performed by Go's ServeMux, allowing an unauthenticated remote attacker to make the server open and return files outside Config.AppDir that are readable by the server process. The confirmed impact is file disclosure only, and the issue is reachable with Dev disabled. This issue is fixed in server version 137_7.
CVE-2026-102657
HIGHPre-NVD 7.57.5ElevatedEG-KEV Tier 3: ElevatedEG-KEV is EchelonGraph's own tiering of exploitation signals from CISA KEV, CISA's SSVC data (Vulnrichment), ransomware data, public exploit-code references and EPSS.Tier 3 is not evidence of exploitation. It means public exploit code is referenced, or CISA's SSVC data says "public PoC", or EPSS ranks the CVE in the top 5%.Signals for this CVE: CISA's SSVC exploitation value: public PoC.EchelonGraph confidence 38%: a heuristic from the tier and the number of signals, not a measured probability.
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-11-09. A secondary CVSS source baseline 7.5; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Also known asEUVD-2026-118494 (ENISA EUVD) · GHSA-g3c2-rjq2-c763 (GitHub Security Advisories)Source: ENISA EUVD
7.5EG
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: 0.7%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHhigh confidence
- EG Risk
- 65EG Risk 65/100
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)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 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
- 0.7%
- EPSS %ILE
- 54th
- 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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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, and whom BOD 26-04 binds: 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.
The score's inputs: 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
November 6, 2026
Last Modified
November 11, 2026
Advisory Details (5)
Auto-updated Nov 6, 2026🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_pr, github_release.
GitHub release Patch Available
Server v137_7
Patch available: esm-dev/esm.sh v137_7
https://github.com/esm-dev/esm.sh/releases/tag/v137_7GitHub commit
commit fc3b345e73ae (esm-dev/esm.sh)
Fix landed in esm-dev/esm.sh commit fc3b345e73ae — awaiting tagged release
https://github.com/esm-dev/esm.sh/commit/fc3b345e73aeaa0b7a05b6f27d91c05fdf5f9b53GitHub commit Patch Available
commit 468b6b2a4b4d (esm-dev/esm.sh)
Patch available: esm-dev/esm.sh v137_7 (contains commit 468b6b2a4b4d)
https://github.com/esm-dev/esm.sh/commit/468b6b2a4b4dfec334cf6b33b01fcd4e5cd93bedGitHub pull request Patch Available
Harden module resolution, registry auth, and web path handling
Patch available: esm-dev/esm.sh v137_7 (PR #1376 merged 2026-07-23)
https://github.com/esm-dev/esm.sh/pull/1376GitHub advisoryMentions a patch (unverified)🟡 PoC Available
web.NewHandler allows arbitrary file read via encoded dot-segment path traversal · Advisory · esm-dev/esm.sh · GitHub
https://github.com/esm-dev/esm.sh/security/advisories/GHSA-g3c2-rjq2-c763Vendor Advisories for CVE-2026-102657(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| go | github.com/esm-dev/esm.sh/web @ 0.2.0 (fixes < 0.2.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| github.com/esm-dev/esm.sh/web | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 13× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-12 16:32 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-11 16:37 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-11 05:28 UTCEchelonGraph re-scored
- 2026-11-11 05:28 UTCGHSA enrichmentGHSA-g3c2-rjq2-c763 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-11 03:42 UTCEchelonGraph re-scored
- 2026-11-11 03:41 UTCGHSA enrichmentGHSA-g3c2-rjq2-c763 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-11 03:34 UTCEchelonGraph re-scored
- 2026-11-11 03:34 UTCGHSA enrichmentGHSA-g3c2-rjq2-c763 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-10 16:41 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-09 22:45 UTCEchelonGraph re-scored
- 2026-11-09 22:45 UTCGHSA enrichmentGHSA-g3c2-rjq2-c763 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-09 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-08 16:37 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-07 16:37 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-06 22:04 UTCENISA EUVD ID recordedEUVD-2026-118494 · Source: ENISA EUVD
- 2026-11-06 21:27 UTCEchelonGraph re-scored
- 2026-11-06 20:57 UTCEchelonGraph re-scoredFirst assessed: 7.5 HIGH
- 2026-11-06 20:56 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-102657?
CVE-2026-102657 is a high-severity vulnerability; its CVE record was published on November 6, 2026. esm.sh is a no-build content delivery network (CDN) for web development. Prior to server version 137_7, the documented web.NewHandler static file server in web/handler.go joins the URL-decoded r.URL.Path with Config.AppDir without verifying that the result remains inside the configured application…
When was the CVE record for CVE-2026-102657 published?
The CVE record for CVE-2026-102657 was published on November 6, 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 November 11, 2026; the record at its source may have been updated since.
Is CVE-2026-102657 actively exploited?
CVE-2026-102657 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102657?
CVE-2026-102657 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102657?
A fix for CVE-2026-102657 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-102657 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-102657
Is Your Infrastructure Affected by CVE-2026-102657?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.