CVE-2026-42155Public exploitNetwork attack vector

Session hijacking via predictable API tokens

Published May 15, 2026 · Updated May 15, 2026

Insufficiently random API session IDs in OpenMage LTS before 20.18.0 allow remote attackers to hijack active XML-RPC or SOAP sessions. The Mage_Api_Model_Session::start method hashes the current time and PHP uniqid output with MD5, producing predictable tokens instead of CSPRNG output. Exploitation requires estimating a victim login time and PHP LCG state, then brute-forcing the unthrottled API; success grants the victim API user's read and write permissions.

CVSS severity9.3
Critical
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficiently random API session IDs in OpenMage LTS before 20.18.0 allow remote attackers to hijack active XML-RPC or SOAP sessions. The Mage_Api_Model_Session::start method hashes the current time and PHP uniqid output with MD5, producing predictable tokens instead of CSPRNG output. Exploitation requires estimating a victim login time and PHP LCG state, then brute-forcing the unthrottled API; success grants the victim API user's read and write permissions.

The record

CVE
CVE-2026-42155
Published
May 15, 2026
Updated
May 15, 2026
Vendor
OpenMage
Product
OpenMage LTS
Classifications
CWE-331, CWE-330, CWE-338, T1550.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 15, 2026CVE publishedPublication date reported by the CVE source.
  2. May 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 20.18.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenMage · OpenMage LTSversion=< 20.18.0

Published CVSS scores

9.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-331Insufficient Entropy
CWE-330Use of Insufficiently Random Values
CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
T1550.004Use Alternate Authentication Material: Web Session Cookie

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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