How severe is GHSA-wjmf-p669-5m5p?

No CVSS score has been assigned to GHSA-wjmf-p669-5m5p yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-wjmf-p669-5m5p?

GHSA-wjmf-p669-5m5p affects the following packages: protego (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-wjmf-p669-5m5p?

Update protego to 0.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wjmf-p669-5m5p is resolved across your whole dependency graph.

How do I detect GHSA-wjmf-p669-5m5p in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protego, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-wjmf-p669-5m5p if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-wjmf-p669-5m5p actively exploited in the wild?

No public exploit code has been indexed for GHSA-wjmf-p669-5m5p yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-wjmf-p669-5m5p?

GHSA-wjmf-p669-5m5p has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-wjmf-p669-5m5p?

GHSA-wjmf-p669-5m5p is classified as Uncontrolled Resource Consumption (CWE-400), CWE-1333 (CWE-1333). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-wjmf-p669-5m5p published, and has it been updated?

GHSA-wjmf-p669-5m5p was published on August 28, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

Protego has exponential backtracking ReDoS in robots.txt URL wildcard matchingGHSA-wjmf-p669-5m5p

Fix: scrapy/protego@7859401

GHSA-wjmf-p669-5m5p is a Uncontrolled Resource Consumption vulnerability in protego. A fix is available for protego — see the affected versions and patch details below.

Also known asCVE-2026-55520PYSEC-2026-3906

Published

Aug 28, 2026

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-wjmf-p669-5m5p.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍protego

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Problem description

Protego constructs regular expressions to match URLs against robots.txt Allow: and Disallow: directives, see protego._urlpattern._URLPattern._prepare_pattern_for_regex(). Every * in the directive value is translated into a lazy .*? regex piece, thus a specially crafted directive value with many asterisks may produce a regex that freezes the parser due to exponential backtracking.

Impact

Parsing a specially crafted robots.txt with protego.Protego.parse() and then trying to match an URL with protego.Protego.can_fetch() results in the latter call not returning for a period dependent on the length of the URL.

Proof of concept

from protego import Protego

robotstxt = f"""
User-agent: *
Disallow: /{"*1" * 12}*Z
"""
rp = Protego.parse(robotstxt)
url = "/" + "1" * 60
rp.can_fetch(url, "mybot")  # freezes

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`protego`	all versions	0.6.2`pip install --upgrade 'protego==0.6.2'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protego, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update protego to 0.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wjmf-p669-5m5p is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This Moderate denial of service flaw in Protego, a robots.txt parser, does not affect Red Hat products as the vulnerable component is only shipped in Fedora. This vulnerability has been fixed in upstream version 0.6.2.

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for GHSA-wjmf-p669-5m5p (CC BY 4.0)

Frequently Asked Questions

### Problem description Protego constructs regular expressions to match URLs against `robots.txt` `Allow:` and `Disallow:` directives, see `protego._urlpattern._URLPattern._prepare_pattern_for_regex()`. Every `*` in the directive value is translated into a lazy `.*?` regex piece, thus a specially crafted directive value with many asterisks may produce a regex that freezes the parser due to exponential backtracking. ### Impact Parsing a specially crafted `robots.txt` with `protego.Protego.parse()` and then trying to match an URL with `protego.Protego.can_fetch()` results in the latter call n

O3 Security · Impact-Aware SCA

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