CVE-2021-42009: Apache Traffic Control Traffic Ops Email Injection Vulnerability
Noroxi assessment
Priority: Monitor (action score 18/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 2.8% (FIRST EPSS); higher than 86.6% of all records.
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: github.com/apache/trafficcontrol (Go) 5.1.3, 5.1.3+incompatible.
Low priority for now. Upgrade to github.com/apache/trafficcontrol (Go) 5.1.3, 5.1.3+incompatible or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
An authenticated Apache Traffic Control Traffic Ops user with Portal-level privileges can send a request with a specially-crafted email subject to the /deliveryservices/request Traffic Ops endpoint to send an email, from the Traffic Ops server, with an arbitrary body to an arbitrary email address. Apache Traffic Control 5.1.x users should upgrade to 5.1.3 or 6.0.0. 4.1.x users should upgrade to 5.1.3.
- Published
- Oct 12, 2021
- Updated
- Jun 17, 2026
- EPSS
- 2.8% · 86th percentile
- CWE
- CWE-20
Report tools
Action score
18
Monitor
Low priority for now.
- CVSS
- 17 / 40 · 4.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.8%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| apache | traffic control | cpe:2.3:a:apache:traffic_control |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache traffic control4.1.0 and later · before 5.1.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.
Apache Software Foundation Apache Traffic Control
- 4.0.0 and later · before Apache Traffic Control*affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Go | github.com/apache/trafficcontrol | before 5.1.3 | 5.1.3 |
| Go | github.com/apache/trafficcontrol | before 5.1.3+incompatible | 5.1.3+incompatible |
Same product
apache: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-45387Apache Traffic Control: SQL Injection in Traffic Ops endpoint PUT deliveryservice_request_comments55Plan
- CVE-2021-43350LDAP filter injection vulnerability in Traffic Ops40Plan
- CVE-2019-12405Improper authentication is possible in Apache Traffic Control versions 3.0.0 and 3.0.1 if LDAP is enabled for login in the Traffic Ops API c40Plan
Published before and after this one in the same product
- ← EarlierCVE-2017-7670Jul 10, 2017 · The Traffic Router component of the incubating Apache Traffic Control project is vulnerable to a Slowloris style Denial of Service attack.31Monitor
- ← EarlierCVE-2020-17522Jan 26, 2021 · When ORT (now via atstccfg) generates ip_allow.config files in Apache Traffic Control 3.0.0 to 3.1.0 and 4.0.0 to 4.1.0, those files include24Monitor
- Later →CVE-2022-23206Feb 6, 2022 · Server-Side Request Forgery in Traffic Ops endpoint POST /user/login/oauth31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Go:github.com/apache/trafficcontrol | 5.1.3 | Package registry (OSV) |
| Go:github.com/apache/trafficcontrol | 5.1.3+incompatible | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- low · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
- 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
- lists.apache.org/thread.html/rf0481b9e38ece1ece458d3ce7b2d671df819e3555597f31fc34f084e%40%3Ccommits.trafficcontrol.apache.org%3E
Vendor advisories and official records. Exploit/PoC links are deliberately left out.