CVE-2026-49856

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 89% 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
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

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

@jshookmcp/jshook is an MCP server that gives AI agents tools for JavaScript analysis and security research. In version 0.3.1, he network domain has a central SSRF authorization policy that blocks private, loopback, link-local, and reserved targets unless an explicit authorization object allows private network access. The policy is enforced by raw HTTP/TCP/TLS RTT tools, but the ICMP probe and traceroute tools resolve the target and invoke the native ICMP/traceroute sink directly. An MCP client with access to an active network domain can therefore ask the jshookmcp server to probe internal addresses even when local SSRF access is disabled for the other raw network tools. This exposes an internal reachability and route mapping primitive from the server network position. Version 0.3.2 fixes the issue.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

July 1, 2026

Last Modified

August 13, 2026

Advisory Details (2)

Auto-updated Aug 13, 2026
Patch available. Sources: github_commit, github.
github Patch Available

ICMP probe and traceroute skip local-network SSRF authorization · Advisory · vmoranv/jshookmcp · GitHub

https://github.com/vmoranv/jshookmcp/security/advisories/GHSA-c5r6-m4mr-8q5j
github_commit

commit 02111311f7bd (vmoranv/jshookmcp)

Fix landed in vmoranv/jshookmcp commit 02111311f7bd — awaiting tagged release

https://github.com/vmoranv/jshookmcp/commit/02111311f7bd0f86a7d7ef8538986594b3a18afa

Vendor Advisories for CVE-2026-49856(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 rangeFixed inDependents
@jshookmcp/jshook0.3.10.3.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 38× 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. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-07 16:01 UTCEPSS rescore
  4. 2026-09-06 13:47 UTCEPSS rescore
  5. 2026-09-06 02:20 UTCEG score recompute
  6. 2026-09-04 05:06 UTCEPSS rescore
  7. 2026-09-02 14:12 UTCEPSS rescore
  8. 2026-09-01 13:54 UTCEPSS rescore
  9. 2026-09-01 04:40 UTCEPSS rescore
  10. 2026-08-30 19:17 UTCEPSS rescore
  11. 2026-08-30 11:46 UTCEG score recompute
  12. 2026-08-30 01:22 UTCEPSS rescore
  13. 2026-08-28 21:41 UTCEPSS rescore
  14. 2026-08-27 22:26 UTCEG score recompute
  15. 2026-08-27 14:25 UTCEPSS rescore
  16. 2026-08-26 14:46 UTCEPSS rescore
  17. 2026-08-25 13:49 UTCEPSS rescore
  18. 2026-08-24 14:59 UTCEG score recompute
  19. 2026-08-23 13:24 UTCEG score recompute
  20. 2026-08-23 00:19 UTCEPSS rescore
  21. 2026-08-22 11:33 UTCEG score recompute
  22. 2026-08-21 23:49 UTCEPSS rescore
  23. 2026-08-21 10:00 UTCEG score recompute
  24. 2026-08-20 22:55 UTCEPSS rescore
  25. 2026-08-20 08:28 UTCEG score recompute
Show 17 more
  1. 2026-08-19 17:04 UTCEPSS rescore
  2. 2026-08-19 06:55 UTCEG score recompute
  3. 2026-08-18 13:48 UTCEPSS rescore
  4. 2026-08-18 04:50 UTCEG score recompute
  5. 2026-08-17 13:47 UTCEPSS rescore
  6. 2026-08-16 22:58 UTCEG score recompute
  7. 2026-08-16 14:56 UTCEPSS rescore
  8. 2026-08-16 02:14 UTCEPSS rescore
  9. 2026-08-15 21:25 UTCEG score recompute
  10. 2026-08-15 01:30 UTCEPSS rescore
  11. 2026-08-13 18:19 UTCEG score recompute
  12. 2026-08-13 17:51 UTCEG score recompute
  13. 2026-08-13 15:28 UTCEG score recompute
  14. 2026-07-30 23:36 UTCEG score recompute
  15. 2026-07-26 13:16 UTCEG score recompute
  16. 2026-07-23 03:18 UTCEG score recompute
  17. 2026-07-01 19:05 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-49856?
CVE-2026-49856 is a medium vulnerability published on July 1, 2026. @jshookmcp/jshook is an MCP server that gives AI agents tools for JavaScript analysis and security research. In version 0.3.1, he network domain has a central SSRF authorization policy that blocks private, loopback, link-local, and reserved targets unless an explicit authorization object allows…
When was CVE-2026-49856 disclosed?
CVE-2026-49856 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49856 actively exploited?
CVE-2026-49856 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 88.9% of all scored CVEs.
What is the CVSS score of CVE-2026-49856?
CVE-2026-49856 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-49856?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49856, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49856

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