How severe is CVE-2026-8727?

No CVSS score has been assigned to CVE-2026-8727 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-8727?

CVE-2026-8727 affects the following packages: tomasnorre/crawler (Packagist), tomasnorre/crawler (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-8727?

Update tomasnorre/crawler to 12.0.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-8727 is resolved across your whole dependency graph.

How do I detect CVE-2026-8727 in my Packagist dependencies?

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

How do I mitigate CVE-2026-8727 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2026-8727 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-8727 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 CVE-2026-8727?

CVE-2026-8727 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 41th 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 CVE-2026-8727?

CVE-2026-8727 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-8727 published, and has it been updated?

CVE-2026-8727 was published on May 19, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-8727 — tomasnorre/crawler

CVE-2026-8727 is a Deserialization of Untrusted Data vulnerability in tomasnorre/crawler. A fix is available for tomasnorre/crawler — see the affected versions and patch details below.

Remote Code Execution in extension "Site Crawler" (crawler)

Also known asGHSA-jr8m-x4p7-p3v5

Published

May 19, 2026

Updated

Aug 12, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
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 CVE-2026-8727.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs41th percentile — riskier than 41% of all scored CVEsHighest risk

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

Real-World Exposure

2 pkgs affected

🐘tomasnorre/crawler🐘tomasnorre/crawler

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

Description

The TYPO3 Crawler extension passes the X-T3Crawler-Meta response header from crawled URLs directly to PHP's unserialize(). An attacker controlling a crawled endpoint can inject arbitrary serialized PHP objects, leading to Remote Code Execution on the TYPO3 server. Exploitation requires administrative privileges to configure a crawler-enabled page and trigger the crawl via a Scheduler task. This has been patched in versions 12.0.11 and 11.0.13.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`tomasnorre/crawler`	≥ 12.0.0&&< 12.0.11	12.0.11`composer require tomasnorre/crawler:^12.0.11`
🐘Packagist	`tomasnorre/crawler`	all versions	11.0.13`composer require tomasnorre/crawler:^11.0.13`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tomasnorre/crawler, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tomasnorre/crawler to 12.0.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-8727 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

The TYPO3 Crawler extension passes the X-T3Crawler-Meta response header from crawled URLs directly to PHP's `unserialize()`. An attacker controlling a crawled endpoint can inject arbitrary serialized PHP objects, leading to Remote Code Execution on the TYPO3 server. Exploitation requires administrative privileges to configure a crawler-enabled page and trigger the crawl via a Scheduler task. This has been patched in versions 12.0.11 and 11.0.13.

O3 Security · Impact-Aware SCA

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