CVE-2026-49864

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 74% 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
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: Elevated riskExposed: 0

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

wetty provides terminal access in browser over http/https. Prior to version 3.0.4, the wetty client decodes a base64 filename from the file-download escape sequence and interpolates it raw into a Toastify HTML string (escapeMarkup: false). Any output the victim renders - a cat'd file, a tailed log, an SSH MOTD, a curl response - that contains \x1b[5i...:...\x1b[4i runs script in the wetty origin and types attacker-chosen keystrokes into the victim's SSH session. Version 3.0.4 fixes the issue.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
55(Track)
EG Risk 55/100SSVC: 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
Severity86% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

July 1, 2026

Last Modified

September 9, 2026

Advisory Details (1)

Auto-updated Aug 13, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

DOM XSS via file-download filename · Advisory · butlerx/wetty · GitHub

https://github.com/butlerx/wetty/security/advisories/GHSA-p26j-h7wj-r568

Vendor Advisories for CVE-2026-49864(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
wetty—3.0.4—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 46× 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. 2026-09-09 22:59 UTCEG score recompute
  4. 2026-09-08 22:01 UTCEPSS rescore
  5. 2026-09-07 16:01 UTCEPSS rescore
  6. 2026-09-06 15:57 UTCEG score recompute
  7. 2026-09-06 13:47 UTCEPSS rescore
  8. 2026-09-06 02:20 UTCEG score recompute
  9. 2026-09-04 05:06 UTCEPSS rescore
  10. 2026-09-02 14:12 UTCEPSS rescore
  11. 2026-09-01 13:54 UTCEPSS rescore
  12. 2026-09-01 04:40 UTCEPSS rescore
  13. 2026-08-31 00:28 UTCEG score recompute
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 11:46 UTCEG score recompute
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-28 21:41 UTCEPSS rescore
  18. 2026-08-27 22:26 UTCEG score recompute
  19. 2026-08-27 14:25 UTCEPSS rescore
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-25 16:21 UTCEG score recompute
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-24 23:34 UTCEG score recompute
  24. 2026-08-24 10:52 UTCEG score recompute
  25. 2026-08-23 08:55 UTCEG score recompute
Show 25 more
  1. 2026-08-23 00:19 UTCEPSS rescore
  2. 2026-08-22 07:30 UTCEG score recompute
  3. 2026-08-21 23:49 UTCEPSS rescore
  4. 2026-08-21 06:05 UTCEG score recompute
  5. 2026-08-20 22:55 UTCEPSS rescore
  6. 2026-08-20 04:41 UTCEG score recompute
  7. 2026-08-19 17:04 UTCEPSS rescore
  8. 2026-08-18 20:59 UTCEG score recompute
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-18 02:21 UTCEG score recompute
  11. 2026-08-18 01:47 UTCEG score recompute
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 00:37 UTCEG score recompute
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 11:55 UTCEG score recompute
  16. 2026-08-16 02:14 UTCEPSS rescore
  17. 2026-08-15 10:30 UTCEG score recompute
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-13 20:23 UTCEG score recompute
  20. 2026-08-13 19:23 UTCEG score recompute▲ 8.60
  21. 2026-08-13 19:21 UTCMITRE cvelistV5CVSS v3 → 8.6 · CVSS v4 → 8.6
  22. 2026-08-01 08:33 UTCEG score recompute
  23. 2026-07-26 13:16 UTCEG score recompute
  24. 2026-07-23 03:18 UTCEG score recompute
  25. 2026-07-01 19:05 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-49864?
CVE-2026-49864 is a high vulnerability published on July 1, 2026. wetty provides terminal access in browser over http/https. Prior to version 3.0.4, the wetty client decodes a base64 filename from the file-download escape sequence and interpolates it raw into a Toastify HTML string (escapeMarkup: false). Any output the victim renders - a cat'd file, a tailed log,…
When was CVE-2026-49864 disclosed?
CVE-2026-49864 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49864 actively exploited?
CVE-2026-49864 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 66.3% of all scored CVEs.
What is the CVSS score of CVE-2026-49864?
CVE-2026-49864 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-49864?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49864, 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-2026-49864

Explore →

Is Your Infrastructure Affected by CVE-2026-49864?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs