CVE-2021-42009Network attack vector

Arbitrary email relay via unvalidated customer name

Published Oct 12, 2021 · Updated Aug 4, 2024

Email content injection in Apache Traffic Control 4.1.0 through 5.1.2 allows remote authenticated users to send arbitrary email content. The /deliveryservices/request handler placed an unrestricted customer name into generated email content, so crafted subject data could set an arbitrary recipient and body. Portal-level Traffic Ops access is required, and successful use relays the attacker-chosen message from the Traffic Ops server.

CVSS severity4.3
Medium
EPSS probability2.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Email content injection in Apache Traffic Control 4.1.0 through 5.1.2 allows remote authenticated users to send arbitrary email content. The /deliveryservices/request handler placed an unrestricted customer name into generated email content, so crafted subject data could set an arbitrary recipient and body. Portal-level Traffic Ops access is required, and successful use relays the attacker-chosen message from the Traffic Ops server.

The record

CVE
CVE-2021-42009
Published
Oct 12, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Traffic Control
Classifications
CWE-20
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=4.0.0 <Apache Traffic Control* changes=[{"at":"5.0.0","status":"affected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Controlversion=4.0.0 <Apache Traffic Control* changes=[{"at":"5.0.0","status":"affected"}]

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation

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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