CVE-2026-19906Network attack vector

User impersonation via timestamp-derived API keys

Published Aug 15, 2026 · Updated Aug 15, 2026

Insufficient entropy in PKP Web Application Library 3.3.0, 3.4.0, and 3.5.0 allows remote attackers to impersonate users via API keys. APIProfileForm::execute generates each new API key as SHA-1 of the current Unix timestamp, making the value searchable within a small time-derived keyspace. Exploitation requires the key's approximate creation time and the api_key_secret from config.inc.php; the recovered key permits a forged HS256 JWT to authenticate as that user.

CVSS severity6.3
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in PKP Web Application Library 3.3.0, 3.4.0, and 3.5.0 allows remote attackers to impersonate users via API keys. APIProfileForm::execute generates each new API key as SHA-1 of the current Unix timestamp, making the value searchable within a small time-derived keyspace. Exploitation requires the key's approximate creation time and the api_key_secret from config.inc.php; the recovered key permits a forged HS256 JWT to authenticate as that user.

The record

CVE
CVE-2026-19906
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
Public Knowledge Project
Product
PKP Web Application Library
Classifications
CWE-330, CWE-331, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 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=3.3.0
  2. Affected versionversion=3.4.0
  3. Affected versionversion=3.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Public Knowledge Project · PKP Web Application Libraryversion=3.3.0; version=3.4.0; version=3.5.0

Published CVSS scores

6.3VulDBCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
3.7VulDBCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
2.6VulDBAV:N/AC:H/Au:N/C:P/I:N/A: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-330Use of Insufficiently Random Values
CWE-331Insufficient Entropy
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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