CVE-2026-44727

MEDIUMNVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.4 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% 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, nvd
Trending — 3 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

A fix is available — apply it.

Jupyter Server is the backend for Jupyter web applications. Prior to 2.20, the nbconvert HTTP handlers in jupyter_server render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their Content-Security-Policy. Combined with nbconvert.HTMLExporter's default non-sanitizing behavior, a notebook carrying an HTML payload in a display_data output triggers stored XSS with cookie access, full /api/* authority, and kernel RCE. This vulnerability is fixed in 2.20.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

June 18, 2026

Last Modified

July 22, 2026

Advisory Details (2)

Auto-updated Jun 22, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Stored XSS in `NbconvertFileHandler` / `NbconvertPostHandler` via missing `sandbox` CSP · Advisory · jupyter-server/jupyter_server · GitHub

Affected: v2.20.0, commit

https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp
github_commit Patch Available

commit 6cbee8d65e71 (jupyter-server/jupyter_server)

Patch available: jupyter-server/jupyter_server v2.20.0 (contains commit 6cbee8d65e71)

https://github.com/jupyter-server/jupyter_server/commit/6cbee8d65e71abac851c4492fea987ad080580bd

Vendor Advisories for CVE-2026-44727(2)

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 / EcosystemFixed in / PatchReleasedSource
redhatmta/mta-solution-server-rhel9:17841098832026-07-21redhat

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

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
jupyter-server1.10.2-1 ... 2.9.1-1 (28 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
jupyter-server1.23.3-1 ... 2.9.1-1 (14 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
jupyter-server2.15.0-1, 2.17.0-1, 2.20.0-1, 2.20.0-2, 2.20.0-3——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
jupyter-server2.15.0-1, 2.17.0-12.20.0-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
jupyter-server0.0.0 ... 2.9.1 (159 versions)2.20.0—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 74× 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.

Showing the most recent 100 of 123 total refreshes for this CVE.

  1. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-25 07:06 UTCEG score recompute
  4. 2026-08-25 07:06 UTCVendor advisory
  5. 2026-08-24 05:12 UTCVendor advisory
  6. 2026-08-23 01:13 UTCEG score recompute
  7. 2026-08-23 01:13 UTCVendor advisory
  8. 2026-08-23 00:19 UTCEPSS rescore
  9. 2026-08-21 23:49 UTCEPSS rescore
  10. 2026-08-21 11:53 UTCEG score recompute
  11. 2026-08-21 11:53 UTCVendor advisory
  12. 2026-08-20 22:55 UTCEPSS rescore
  13. 2026-08-20 09:45 UTCEG score recompute
  14. 2026-08-20 09:45 UTCVendor advisory
  15. 2026-08-19 17:04 UTCEPSS rescore
  16. 2026-08-19 07:59 UTCEG score recompute
  17. 2026-08-19 07:59 UTCVendor advisory
  18. 2026-08-18 13:48 UTCEPSS rescore
  19. 2026-08-17 13:47 UTCEPSS rescore
  20. 2026-08-17 13:40 UTCEG score recompute
  21. 2026-08-17 13:40 UTCVendor advisory
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 11:54 UTCEG score recompute
  24. 2026-08-16 11:54 UTCVendor advisory
  25. 2026-08-16 02:14 UTCEPSS rescore
Show 75 more
  1. 2026-08-15 10:09 UTCEG score recompute
  2. 2026-08-15 10:09 UTCVendor advisory
  3. 2026-08-15 01:30 UTCEPSS rescore
  4. 2026-08-14 08:23 UTCEG score recompute
  5. 2026-08-14 08:23 UTCVendor advisory
  6. 2026-08-13 22:00 UTCEPSS rescore
  7. 2026-08-13 06:38 UTCEG score recompute
  8. 2026-08-13 06:38 UTCVendor advisory
  9. 2026-08-12 13:51 UTCEPSS rescore
  10. 2026-08-12 04:52 UTCEG score recompute
  11. 2026-08-12 04:52 UTCVendor advisory
  12. 2026-08-11 02:56 UTCEG score recompute
  13. 2026-08-11 02:56 UTCVendor advisory
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 01:10 UTCEG score recompute
  16. 2026-08-10 01:10 UTCVendor advisory
  17. 2026-08-09 13:46 UTCEPSS rescore
  18. 2026-08-08 23:25 UTCEG score recompute
  19. 2026-08-08 23:25 UTCVendor advisory
  20. 2026-08-08 16:37 UTCEPSS rescore
  21. 2026-08-07 21:39 UTCEG score recompute
  22. 2026-08-07 21:39 UTCVendor advisory
  23. 2026-08-06 19:53 UTCEG score recompute
  24. 2026-08-06 19:53 UTCVendor advisory
  25. 2026-08-06 13:46 UTCEPSS rescore
  26. 2026-08-05 19:17 UTCEPSS rescore
  27. 2026-08-05 18:07 UTCVendor advisory
  28. 2026-08-04 16:09 UTCEG score recompute
  29. 2026-08-04 16:09 UTCVendor advisory
  30. 2026-08-04 15:10 UTCEPSS rescore
  31. 2026-08-04 10:38 UTCEPSS rescore
  32. 2026-08-03 14:24 UTCEG score recompute
  33. 2026-08-03 14:24 UTCVendor advisory
  34. 2026-08-03 10:36 UTCEPSS rescore
  35. 2026-08-02 09:40 UTCEG score recompute
  36. 2026-08-02 09:40 UTCVendor advisory
  37. 2026-08-02 02:27 UTCEPSS rescore
  38. 2026-08-01 07:53 UTCEG score recompute
  39. 2026-08-01 07:53 UTCVendor advisory
  40. 2026-08-01 04:16 UTCEPSS rescore
  41. 2026-07-31 05:19 UTCEG score recompute
  42. 2026-07-31 05:19 UTCVendor advisory
  43. 2026-07-30 16:28 UTCEPSS rescore
  44. 2026-07-30 03:33 UTCVendor advisory
  45. 2026-07-29 01:46 UTCEG score recompute
  46. 2026-07-29 01:46 UTCVendor advisory
  47. 2026-07-28 15:36 UTCEPSS rescore
  48. 2026-07-27 22:14 UTCEG score recompute
  49. 2026-07-27 22:14 UTCVendor advisory
  50. 2026-07-27 14:13 UTCEPSS rescore
  51. 2026-07-26 17:43 UTCEG score recompute
  52. 2026-07-26 17:43 UTCVendor advisory
  53. 2026-07-26 14:54 UTCEPSS rescore
  54. 2026-07-26 14:54 UTCEPSS rescore
  55. 2026-07-25 14:18 UTCEPSS rescore
  56. 2026-07-24 14:17 UTCEPSS rescore
  57. 2026-07-23 14:18 UTCEPSS rescore
  58. 2026-07-23 03:15 UTCEG score recompute
  59. 2026-07-22 14:08 UTCEPSS rescore
  60. 2026-07-21 15:24 UTCEPSS rescore
  61. 2026-07-20 17:08 UTCEPSS rescore
  62. 2026-07-19 14:31 UTCEPSS rescore
  63. 2026-07-19 02:29 UTCEPSS rescore
  64. 2026-07-18 10:04 UTCEPSS rescore
  65. 2026-07-16 17:03 UTCEPSS rescore
  66. 2026-07-15 16:57 UTCEPSS rescore
  67. 2026-07-15 06:32 UTCEG score recompute▼ 3.60
  68. 2026-07-15 02:26 UTCNVD updateCVSS v3 → 5.4 · severity → MEDIUM
  69. 2026-07-15 02:00 UTCEPSS rescore
  70. 2026-07-13 06:13 UTCEPSS rescore
  71. 2026-07-12 05:46 UTCEPSS rescore
  72. 2026-07-11 08:27 UTCEPSS rescore
  73. 2026-07-09 19:10 UTCEPSS rescore
  74. 2026-07-08 21:39 UTCEG score recompute▲ 3.60
  75. 2026-07-08 15:16 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-44727?
CVE-2026-44727 is a medium vulnerability published on June 18, 2026. Jupyter Server is the backend for Jupyter web applications. Prior to 2.20, the nbconvert HTTP handlers in jupyterserver render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their Content-Security-Policy. Combined with nbconvert.HTMLExporter's default…
When was CVE-2026-44727 disclosed?
CVE-2026-44727 was first published in the National Vulnerability Database on June 18, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44727 actively exploited?
CVE-2026-44727 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 63.6% of all scored CVEs.
What is the CVSS score of CVE-2026-44727?
CVE-2026-44727 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-44727?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44727, 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-2026-44727

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