CVE-2026-56266: crawl4ai (PyPI)

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
EPSS 0.5%, percentile 40: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 40% of all scored CVEs (low). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Only applies if your dependency tree includes crawl4ai (PyPI) <= 0.8.6, fixed in 0.8.7. Check your lockfile, including transitive dependencies.

What it is

Crawl4AI before 0.8.7 contains a server-side request forgery vulnerability in the /crawl, /crawl/stream, /md, and /llm endpoints that fetch arbitrary user-supplied URLs without validation. Unauthenticated attackers can bypass the internal-address blocklist using IPv6-mapped IPv4 addresses to reach internal services and cloud metadata endpoints.

From the GitHub advisory

Summary

Multiple security vulnerabilities in the Crawl4AI Docker API server affecting endpoints for crawling, markdown/LLM extraction, screenshots, PDFs, webhooks, monitoring, JavaScript execution, and configuration.

Vulnerabilities

1. Arbitrary File Write via /screenshot and /pdf (CWE-22, CVSS 9.1)

The outputpath parameter accepts arbitrary filesystem paths with no validation. An attacker can overwrite server files (DoS) or write to any appuser-writable location.

Weakness type: CWE-918, CWE-22, CWE-79, CWE-94, CWE-306.

Product: crawl4ai (PyPI) · Assigned by: VulnCheck · Published: 2026-06-22

Affected and fixed versions

Ecosystem	Package	Vulnerable	First fixed
PyPI	`crawl4ai`	<= 0.8.6	0.8.7

Vendor	Product	Affected versions (per CVE record)
Crawl4AI	Crawl4AI	< 0.8.7

Severity scores

Scored by	CVSS	Score	Vector
VulnCheck	4.0	9.2 Critical	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`
VulnCheck	3.1	8.6 High	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N`
GitHub	4.0	9.2	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/`

Attack vector: network (remotely reachable)
Attack complexity: low
Attack requirements: none
Privileges required: none (no login)
User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 40.

Timeline

2026-06-16 — GitHub-reviewed advisory GHSA-365w-hqf6-vxfg published (critical)
2026-06-22 — CVE record published by VulnCheck
2026-07-14 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.