CVE-2026-42155
What is CVE-2026-42155?
Magento Long Term Support (LTS) is an unofficial, community-driven project provides an alternative to the Magento Community Edition e-commerce platform with a high level of backward compatibility. Prior to 20.18.0, the XML-RPC / SOAP API session ID is generated using an outdated, time-based construction rather than a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG). All inputs to the MD5 hash are time-derived and non-secure. Because the resulting digest relies entirely on the timestamp and the PHP internal LCG state, the effective entropy is severely constrained. This violates the OWASP ASVS v4 requirement of ≥ 64 bits of entropy (V3.2.2) and NIST SP 800-63B standards. By narrowing the LCG window (via server state leaks or general predictability) and leveraging the lack of API rate-limiting, an attacker can generate a localized pool of candidate MD5 hashes and execute a high-speed online brute-force attack to hijack active API sessions. This vulnerability is fixed in 20.18.0.
FAQ
CVE-2026-42155 has a CVSS score of N/A/10, rated as Unknown. Review the affected products list and apply vendor patches.
CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2026-42155 scores N/A/10 (Unknown). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.
The list of devices confirmed to be affected by CVE-2026-42155 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.
Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.