CVE-2026-42155

Received
Published: 15 May 2026, 17:05
Last modified:15 May 2026, 17:36

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.3 CRITICAL
v4.0 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

15 May 2026, 17:05
Published
Vulnerability first disclosed
15 May 2026, 17:36
Last Modified
Vulnerability information updated

Description

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 Prior to 20.18.0, the XML-RPC / SOAP API session ID is generated using an outdated, time-based construction rather than a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG).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.

CVSS Metrics

  • v4.0•CRITICAL•Score: 9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
  • v4.0•CRITICAL•Score: 9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Techniques & Countermeasures

  • CWE-330•Use of Insufficiently Random Values

    The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

  • CWE-331•Insufficient Entropy

    The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.

  • CWE-338•Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

    The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

Affected Systems

  • openmage•magento-lts

    < 20.18.0

References (1)