CVE-2026-5082Network attack vector

Predictable session IDs via weak random fallback

Published Apr 8, 2026 · Updated Apr 8, 2026

Weak randomness in Amon2::Plugin::Web::CSRFDefender 7.00 through 7.03 allows remote attackers to predict session IDs. generate_session_id hashes output from Perl rand(), the process ID, and high-resolution epoch time with SHA-1 when reading /dev/urandom fails, leaving the identifier derived from guessable inputs. Exploitation requires /dev/urandom to be unavailable; published material does not describe a demonstrated confidentiality or integrity consequence.

CVSS severity5.3
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak randomness in Amon2::Plugin::Web::CSRFDefender 7.00 through 7.03 allows remote attackers to predict session IDs. generate_session_id hashes output from Perl rand(), the process ID, and high-resolution epoch time with SHA-1 when reading /dev/urandom fails, leaving the identifier derived from guessable inputs. Exploitation requires /dev/urandom to be unavailable; published material does not describe a demonstrated confidentiality or integrity consequence.

The record

CVE
CVE-2026-5082
Published
Apr 8, 2026
Updated
Apr 8, 2026
Vendor
Tokuhiro Matsuno
Product
Amon2::Plugin::Web::CSRFDefender
Classifications
CWE-338, CWE-340, CAPEC-62
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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=7.00 <=7.03

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tokuhiro Matsuno · Amon2::Plugin::Web::CSRFDefenderversion=7.00 <=7.03

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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-338Use of Cryptographically Weak Pseudo-Random Number Generator
CWE-340Generation of Predictable Numbers or Identifiers
CAPEC-62Cross Site Request Forgery

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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