CVE-2021-21426 Fixes a bug in Zend Framework's Stream HTTP Wrapper

What is CVE-2021-21426?

CVE-2021-21426 is a critical unsafe deserialization vulnerability in OpenMage magento-lts, published on 21 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Magento-lts is a long-term support alternative to Magento Community Edition (CE). In magento-lts versions 19.4.12 and prior and 20.0.8 and prior, there is a vulnerability caused by the unsecured deserialization of an object. A patch in versions 19.4.13 and 20.0.9 was back ported from Zend Framework 3. The vulnerability was assigned CVE-2021-3007 in Zend Framework.

Weakness: CWE-502

Which versions are affected by CVE-2021-21426?

4 open source packages ship an affected version, including openmage/magento-lts. It affects 1 product.

Products include Openmage Magento.

How do I fix CVE-2021-21426?

Upgrade openmage/magento-lts to a fixed version for your release line: 19.4.13 or 20.0.9.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2021-21426 being exploited?

There is no known exploitation of CVE-2021-21426 in the wild and no public exploit code.

Other vulnerabilities in OpenMage magento-lts

• CVE-2021-21427 Backport for CVE-2021-21024 Blind SQLi from Magento 2 Critical 9.1
• CVE-2021-41144 OpenMage LTS authenticated remote code execution through layout update High 8.8
• CVE-2026-40488 OpenMage LTS has Customer File Upload Extension Blocklist Bypass that Leads to Remote Code Execution High 8.7
• CVE-2026-25524 OpenMage LTS's Phar Deserialization leads to Remote Code Execution High 8.1
• CVE-2020-15244 RCE in Magento High 8.0

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-m496-x567-f98c.