CVE-2026-73299

CRITICALPre-NVD 10.010.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 10.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.8% (77th percentile of EPSS-scored CVEs). 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
10.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.8%CVSS: 10.0Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 0.1.5 and 2.0.0-beta.5, the TypeScript Nunjucks renderer evaluated untrusted .prompty template bodies with unrestricted JavaScript member access. An attacker-controlled template could traverse constructor and prototype properties to execute JavaScript in the host Node.js process. This issue is fixed in versions 0.1.5 and 2.0.0-beta.5.

CVSS v3
10.0
EG Score
10.0CRITICALmedium confidence
EG Risk
61
EG Risk 61/100CISA SSVC

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
Severity100% × 45%
Exploitation2% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
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
1.8%
EPSS %ILE
77th
KEV
Not listed

CISA SSVCTrack 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 none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 12, 2026

Last Modified

September 9, 2026

Advisory Details (6)

Auto-updated Oct 7, 2026
Patch available. Sources: github_commit, github_pr, github.
generic

GitHub - microsoft/prompty at typescript/2.0.0-beta.5 · GitHub

https://github.com/microsoft/prompty/tree/typescript/2.0.0-beta.5
githubMentions a patch (unverified)

Server-Side Template Injection to Remote Code Execution in the @prompty/core Nunjucks Renderer · Advisory · microsoft/prompty · GitHub

https://github.com/microsoft/prompty/security/advisories/GHSA-w28w-gp39-m4p6
github_pr

fix(promptyjs): restrict Nunjucks template execution

Fix merged in microsoft/prompty PR #405 on 2026-07-20 — awaiting tagged release

https://github.com/microsoft/prompty/pull/405
github_pr Patch Available

fix(typescript): restrict Nunjucks template execution

Patch available: microsoft/prompty python/2.0.0 (PR #404 merged 2026-07-20)

https://github.com/microsoft/prompty/pull/404
github_commit

commit f5c57c94a099 (microsoft/prompty)

Fix landed in microsoft/prompty commit f5c57c94a099 — awaiting tagged release

https://github.com/microsoft/prompty/commit/f5c57c94a0990cca79d095c3daab661b4b1fb89f
github_commit Patch Available

commit e4a0ebf49e3a (microsoft/prompty)

Patch available: microsoft/prompty python/2.0.0 (contains commit e4a0ebf49e3a)

https://github.com/microsoft/prompty/commit/e4a0ebf49e3a78d5d7796c8480bf9a4f0c54d19e

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
@prompty/core—
  • every version up to 0.1.5: fixed in 0.1.5
  • 2.0.0-alpha.1 up to 2.0.0-beta.5: fixed in 2.0.0-beta.5
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 48× 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 108 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Same product

2 shown

npm:@prompty/core

Frequently asked(5)

What is CVE-2026-73299?
CVE-2026-73299 is a critical vulnerability published on August 12, 2026. Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 0.1.5 and 2.0.0-beta.5, the TypeScript Nunjucks renderer evaluated untrusted .prompty template bodies with unrestricted JavaScript member access. An attacker-controlled template could traverse constructor and prototype…
When was CVE-2026-73299 disclosed?
CVE-2026-73299 was first published on August 12, 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-2026-73299 actively exploited?
CVE-2026-73299 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.8% probability of exploitation in the next 30 days (77th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73299?
CVE-2026-73299 has a CVSS base score of 10.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73299?
A fix for CVE-2026-73299 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-73299

Explore →

Is Your Infrastructure Affected by CVE-2026-73299?

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

Book a Demo →Browse All CVEs