Modular Max Serve has Unsafe Deserialization vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-60455: 0.33% estimated exploitation activity in the next 30 days; percentile 26.54 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Unsafe Deserialization vulnerability in Modular Max Serve before 25.6, specifically when the "--experimental-enable-kvcache-agent" feature is used allowing attackers to execute arbitrary code.

Published by the source

18 Nov 2025, 21:32 UTC

Last modified by the source

13 Jul 2026, 07:26 UTC

Source last checked

26 Oct 2026, 13:35 UTC

1. Revision 5 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7xcv-9j6c-2fmc

2. Revision 4 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 3 · amended · 24 Oct 2026

   Amended from osv record PYSEC-2025-253

4. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-7xcv-9j6c-2fmc

5. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-7xcv-9j6c-2fmc

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# Patch Next advisory brief: CVE-2025-60455

Advisory: Modular Max Serve has Unsafe Deserialization vulnerability
IDs: CVE-2025-60455, GHSA-7xcv-9j6c-2fmc
Record: https://patchnext.com/advisories/cve-2025-60455 (revision 5, source checked 26 Oct 2026, 13:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: modular 25.6.0; max 25.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI modular: affected < 25.6.0; fixed in 25.6.0
- PyPI max: affected < 25.6.0; fixed in 25.6.0

## Suggested inspection (read-only)
- `python -m pip show modular`: prints the installed version. Run with the environment that serves production active.
- `python -m pip show max`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on modular, max.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7xcv-9j6c-2fmc (GitHub-reviewed advisory GHSA-7xcv-9j6c-2fmc lists affected ranges: PyPI modular >=0 <25.6.0)
- Verified: https://osv.dev/vulnerability/GHSA-7xcv-9j6c-2fmc (OSV record GHSA-7xcv-9j6c-2fmc lists affected ranges: PyPI modular >=0 <25.6.0 (fixed))
- Verified: https://osv.dev/vulnerability/PYSEC-2025-253 (OSV record PYSEC-2025-253 lists affected ranges: PyPI max >=0 <25.6.0 (fixed))

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