CVE-2026-73299: Prompty is a markdown file format (.prompty) for LLM prompts

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CRITICAL 10.0REMOTE

CVE-2026-73299 is a critical-severity flaw (CVSS 10.0) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.8% (top 22%)
CISA exploited list	No
Weakness	CWE-94, CWE-1336
Published	2026-08-12
Last modified	2026-10-23

Publisher (CNA): GitHub, Inc.

Timeline

2026-08-12 18:18 UTCPublished CVE record published
2026-10-23 19:10 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · diffoscope · FIXED · 335-1.fc46 · FEDORA-2026-e4c4cc0856 · source

sudo dnf upgrade --advisory=FEDORA-2026-e4c4cc0856

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

References

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