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CVE-2021-3689

Use of Predictable Algorithm in Random Number Generator in yiisoft/yii2

No known exploitation. EPSS puts it in the 80th percentile. Fixed in 2.0.43.

CVSS 3.17.5HighEPSS percentile80th1.9% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix2.0.43Upgrade to this build

Published Updated Sources: CVE.org, NVD, GitHub

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Yiisoft/yii2Affected: ≥ unspecified, ≤ 2.0.42.1Upgrade to: after 2.0.42.1Stated by: CVE record
  • Packagist yiisoft/yii2-devAffected: < 2.0.43Upgrade to: 2.0.43Stated by: GitHub advisory
  • Yiiframework YiiAffected: ≥ 2.0.0, < 2.0.43Upgrade to: 2.0.43Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free Nuclei check exists for this CVE. Run it against your hosts.Is your organisation exposed?Discuss checks for your systems with a specialist. Scope is agreed before testing.

What it is

From the CVE record

yii2 is vulnerable to Use of Predictable Algorithm in Random Number Generator

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS80th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

1.9% chance of exploitation activity in the next 30 days, which ranks it in the 80th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

6 events over 1669 days, from the signal feeds we watch.

  1. Nuclei check added
  2. Patch availablerecord updated
  3. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability NoneNo availability impact

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 1 more reference. See all after sign-in

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