Email header and SMTP command injection via CRLF
Published Jul 14, 2026 · Updated Jul 14, 2026
CRLF injection in the Symfony MIME component allows remote authenticated users to forge email headers or inject SMTP commands. The Address constructor accepts raw CRLF bytes inside a quoted email local-part and later emits the stored value unchanged into message headers and SMTP envelope commands. Exploitation requires an application to pass attacker-controlled address input into Address, and the demonstrated consequence is manipulation of outbound email or SMTP data.
Summary
What happened
CRLF injection in the Symfony MIME component allows remote authenticated users to forge email headers or inject SMTP commands. The Address constructor accepts raw CRLF bytes inside a quoted email local-part and later emits the stored value unchanged into message headers and SMTP envelope commands. Exploitation requires an application to pass attacker-controlled address input into Address, and the demonstrated consequence is manipulation of outbound email or SMTP data.
The record
- CVE
- CVE-2026-45067
- Published
- Jul 14, 2026
- Updated
- Jul 14, 2026
- Vendor
- Symfony
- Product
- Symfony
- Classifications
- CWE-93, T1565.002
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 14, 2026CVE publishedPublication date reported by the CVE source.
- Jul 14, 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.
- Affected versionversion=< 5.4.52
- Affected versionversion=>= 6.0.0-BETA1, < 6.4.40
- Affected versionversion=>= 7.0.0-BETA1, < 7.4.12
- Affected versionversion=>= 8.0.0-BETA1, < 8.0.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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