How severe is CVE-2021-3007?

CVE-2021-3007 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-3007?

CVE-2021-3007 affects the following packages: zendframework/zendframework (Packagist), laminas/laminas-http (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-3007?

No patched version of zendframework/zendframework has shipped for CVE-2021-3007 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2021-3007 in my Packagist dependencies?

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

How do I mitigate CVE-2021-3007 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-2021-3007 actively exploited in the wild?

Yes. There are 5 known exploit references for CVE-2021-3007, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-3007?

CVE-2021-3007 has an EPSS (Exploit Prediction Scoring System) score of 75.3%, placing it in the 100th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-3007?

CVE-2021-3007 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.

Is there exploit tooling available for CVE-2021-3007?

A Nuclei detection template exists for CVE-2021-3007, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-3007 published, and has it been updated?

CVE-2021-3007 was published on January 4, 2021 and was last updated on July 9, 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

CRITICAL severity

CVE-2021-3007 — zendframework

CRITICALFix: laminas/laminas-http#48

CVE-2021-3007 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in zendframework/zendframework. 5 public exploit references exist, so weaponization risk is real. A fix is available for zendframework/zendframework — see the affected versions and patch details below.

Remote code execution in zendframework and laminas-http

Also known asGHSA-xx8f-qf9f-5fgw

Published

Jan 4, 2021

Updated

Jul 9, 2026

Affected

2 pkgs

Patched

1 / 2

Exploits

5 known

Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

75.3%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-3007 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected

🐘zendframework/zendframework🐘laminas/laminas-http

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

Laminas Project laminas-http before 2.14.2, and Zend Framework 3.0.0, has a deserialization vulnerability that can lead to remote code execution if the content is controllable, related to the __destruct method of the Zend\Http\Response\Stream class in Stream.php. NOTE: Zend Framework is no longer supported by the maintainer. NOTE: the laminas-http vendor considers this a "vulnerability in the PHP language itself" but has added certain type checking as a way to prevent exploitation in (unrecommended) use cases where attacker-supplied data can be deserialized

Affected Packages

2 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`zendframework/zendframework`	all versions	No fix
🐘Packagist	`laminas/laminas-http`	all versions	2.14.2`composer require laminas/laminas-http:^2.14.2`

Affected Products

2 products · 2 configurations

Application

laminas-httpgetlaminas

< 2.14.2

range

Application

zend frameworkzend

1 version

3.0.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.