# CVE-2026-55520

## Summary

- **CVE ID:** CVE-2026-55520
- **Severity:** HIGH
- **CVSS Score:** 7.1 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-400, CWE-1333
- **Published:** Aug 28, 2026
- **Last Modified:** Aug 31, 2026

## Description

Protego is a pure-Python robots.txt parser with support for modern conventions. Prior to 0.6.2, protego._urlpattern._URLPattern._prepare_pattern_for_regex translates every asterisk in an Allow or Disallow directive into a lazy regular-expression wildcard, so a directive containing many asterisks creates exponential backtracking. After protego.Protego.parse processes a crafted robots.txt file, protego.Protego.can_fetch can spend an attacker-controlled period matching a near-miss URL and deny service to the crawler. The vulnerable path is src/protego/_urlpattern.py in the _URLPattern match logic. This issue is fixed in version 0.6.2.

## Affected Products

- scrapy — protego (< 0.6.2)

## References

- [CNA](https://github.com/scrapy/protego/security/advisories/GHSA-wjmf-p669-5m5p)
- [CNA](https://github.com/scrapy/protego/commit/785940181659bf440ba82f1da148fade5087e858)
- [CNA](https://github.com/scrapy/protego/releases/tag/0.6.2)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.37%
- **EPSS Percentile:** 30.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._