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Fencer Intel
high 7.5

GHSA-cg3c-5x66-h9cc json

Attacker-controlled regex in RegexSearchTransform can block a FastMCP worker

published 25d ago modified 25d ago

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository PrefectHQ/fastmcp. GitHub has not reviewed it into the GitHub Advisory Database and no CVE record has reached us yet, so everything here comes from the maintainers alone. Read the full advisory on GitHub.

cvss
7.5
version 3.1, the maintainers
cisa kev
Not listed
not in CISA's catalog
epss
—
no score, EPSS covers CVEs only
public exploits
0
none known

Summary

Security advisory published by the maintainers of PrefectHQ/fastmcp for fastmcp and fastmcp-slim: the maintainers' own advisory, not a reviewed GitHub Advisory Database entry. The full advisory is on GitHub.

Patch / fix

  • pypi fastmcp 3.4.9, 4.1.1
  • pypi fastmcp-slim 4.1.1

Is GHSA-cg3c-5x66-h9cc in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CVSS scores

assigned by version score vector
the maintainers 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi fastmcp
>=3.1.0, <3.4.9
>=4.0.0a1, <4.1.1
3.4.9
4.1.1
pypi fastmcp-slim
>=4.0.0a1, <4.1.1
4.1.1

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of PrefectHQ/fastmcp published their own advisory on GitHub. Its facts and headline are shown here; the description stays on GitHub.