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: 1.2%, top 34% 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
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%CVSS: 10.0Exploit: None knownExposed: 0

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

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
10.0(medium)
EG Risk
60(Track)
EG Risk 60/100SSVC: 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
Severity100% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
66%
KEV
Not listed

Published

August 12, 2026

Last Modified

August 12, 2026

Advisory Details (6)

Auto-updated Aug 19, 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
github Patch Available

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

fix(typescript): restrict Nunjucks template execution

Fix merged in microsoft/prompty PR #404 on 2026-07-20 — awaiting tagged release

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

commit e4a0ebf49e3a (microsoft/prompty)

Fix landed in microsoft/prompty commit e4a0ebf49e3a — awaiting tagged release

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

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@prompty/core—0.1.5—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 31× 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. 2026-08-25 15:59 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 14:27 UTCEG score recompute
  4. 2026-08-24 10:09 UTCEG score recompute
  5. 2026-08-23 04:21 UTCEG score recompute
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-22 02:50 UTCEG score recompute
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-21 01:18 UTCEG score recompute
  10. 2026-08-20 22:56 UTCEPSS rescore
  11. 2026-08-19 19:18 UTCEG score recompute
  12. 2026-08-19 17:04 UTCEPSS rescore
  13. 2026-08-18 17:19 UTCEG score recompute
  14. 2026-08-18 13:49 UTCEPSS rescore
  15. 2026-08-18 13:49 UTCEPSS rescore
  16. 2026-08-17 15:08 UTCEG score recompute
  17. 2026-08-17 13:47 UTCEPSS rescore
  18. 2026-08-16 17:54 UTCEG score recompute
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 14:56 UTCEPSS rescore
  21. 2026-08-16 05:08 UTCEG score recompute
  22. 2026-08-16 02:15 UTCEPSS rescore
  23. 2026-08-15 03:39 UTCEG score recompute
  24. 2026-08-15 01:31 UTCEPSS rescore
  25. 2026-08-14 02:08 UTCEG score recompute
Show 6 more
  1. 2026-08-13 22:00 UTCEPSS rescore
  2. 2026-08-12 20:20 UTCEG score recompute
  3. 2026-08-12 19:22 UTCEG score recompute
  4. 2026-08-12 18:38 UTCEG score recompute
  5. 2026-08-12 17:51 UTCEG score recompute
  6. 2026-08-12 17:50 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

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 in the National Vulnerability Database on August 12, 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% probability of exploitation in the next 30 days, which ranks it in the top 33.7% of all scored CVEs.
What is the CVSS score of CVE-2026-73299?
CVE-2026-73299 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2026-73299?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73299, 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

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