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CVE-2021-42009

19
FAUCET Score

CVE-2021-42009 describes an improper input validation vulnerability in Apache Traffic Control, affecting versions 4.1.x and 5.1.x. An authenticated user with Portal-level privileges can craft a malicious email subject to the /deliveryservices/request endpoint, enabling the sending of arbitrary emails from the Traffic Ops server to any address. This is a medium-severity vulnerability (CVSS 4.3) with low attack complexity, allowing for impact on integrity (sending unauthorized emails) without affecting confidentiality or availability. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 4.1.0, < 5.1.3CPE matchmatch criteria
cpe:2.3:a:apache:traffic_control:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.73%
Probability of exploitation in next 30 days
EPSS Percentile
84.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0273 is in the 94th percentile among its peer group of 21,957 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

gopatch availablevia ghsa
Product: github.com/apache/trafficcontrolFixed in: 5.1.3

Vendor Advisories (1)

goGHSA-gw97-f6h8-gm94medium

Email relay in Apache Traffic Control

Oct 13, 2021

References

lists.apache.org / thread.html/r78d471d8a4fd268a4c5ae6c47327c09d9d4b4467c31da2c97422febb%40%3Cdev.trafficcontrol.apache.org%3E
lists.apache.org / thread.html/r7dfa9a89b39d06caeeeb7b5cdc41b3493a9b86cc6cfa059d3f349d87%40%3Cannounce.apache.org%3E
lists.apache.org / thread.html/re384fd0f44c6d230f31376153c6e8b59e4a669f927c1533d06d702af%40%3Cdev.trafficcontrol.apache.org%3E
Mailing ListVendor Advisory
lists.apache.org / thread.html/rf0481b9e38ece1ece458d3ce7b2d671df819e3555597f31fc34f084e%40%3Ccommits.trafficcontrol.apache.org%3E
Mailing ListPatchVendor Advisory
openwall.com / lists/oss-security/2021/10/12/1
Mailing ListThird Party Advisory