Prompty: Arbitrary File Read via ${file:path} Reference Expansion

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 2.0.0-beta.2, Prompty loaders expanded ${file:...} references in .prompty frontmatter without enforcing that resolved paths stayed within the prompt directory or allowed roots, allowing an attacker-controlled prompt file to read local files through absolute paths, .. traversal, or symlink escapes. This issue is fixed in versions 2.0.0-beta.2.

Source published

16 Jul 2026 14:59:01 UTC

Source modified

17 Jul 2026 14:06:36 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Prompty is a markdown file format (.prompty) for LLM prompts. Prior to 2.0.0-beta.2, Prompty loaders expanded ${file:...} references in .prompty frontmatter without enforcing that resolved paths stayed within the prompt directory or allowed roots, allowing an attacker-controlled prompt file to read local files through absolute paths, .. traversal, or symlink escapes. This issue is fixed in versions 2.0.0-beta.2.

Source published

16 Jul 2026 16:19:12 UTC

Source modified

24 Oct 2026 20:10:00 UTC

Observed here

25 Oct 2026 13:17:16 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

## Summary Prompty loaders expanded `${file:...}` references in `.prompty` frontmatter without enforcing that the resolved path stayed within an authorized directory. An attacker-controlled prompt file could use path traversal or an absolute path to cause the host application to read files accessible to the process. ## Affected packages - PyPI `prompty` versions `<= 2.0.0b1`; fixed in `2.0.0b2` - npm `@prompty/core` versions `<= 2.0.0-beta.1`; fixed in `2.0.0-beta.2` - crates.io `prompty` versions `<= 2.0.0-beta.1`; fixed in `2.0.0-beta.2` - NuGet `Prompty.Core` versions `<= 2.0.0-beta.1`; fixed in `2.0.0-beta.2` ## Impact Applications that load untrusted `.prompty` files, user-provided prompt paths, or prompt bundles from less-trusted locations could disclose local files available to the application process when expanded values are logged, returned, or otherwise exposed. ## Remediation Upgrade to the fixed runtime version for your ecosystem. The fix makes file references secure by default: `${file:...}` may only resolve within the directory tree containing the `.prompty` file. Host applications that need shared prompt assets outside that tree must explicitly provide allowed file roots through runtime load options. Absolute paths, `..` traversal, and symlink escapes outside allowed roots are rejected. ## Fix details The patched runtimes canonicalize file-reference targets and allowed roots before reading referenced files, reject targets outside the prompt directory by default, and add regression coverage for traversal, absolute paths, explicit allowlists, and symlink escapes. The release commit is `88ac9948d7d37995edbb2f6d36913436626c39e1`.

Source published

17 Jul 2026 19:46:05 UTC

Source modified

31 Jul 2026 05:15:34 UTC

Observed here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Publisher rating · HIGH