What’s Vulnerable › Vulnerabilities
CVE-2017-15042
- Severity: medium (CVSS 5.9 v3.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2017-10-05 · updated 2026-06-17
- Weakness: CWE-319
Description
An unintended cleartext issue exists in Go before 1.8.4 and 1.9.x before 1.9.1. RFC 4954 requires that, during SMTP, the PLAIN auth scheme must only be used on network connections secured with TLS. The original implementation of smtp.PlainAuth in Go 1.0 enforced this requirement, and it was documented to do so. In 2013, upstream issue #5184, this was changed so that the server may decide whether PLAIN is acceptable. The result is that if you set up a man-in-the-middle SMTP server that doesn't advertise STARTTLS and does advertise that PLAIN auth is OK, the smtp.PlainAuth implementation sends the username and password.
Affected products
- Go: through 1.8.3; 1.9
References
- http://www.securityfocus.com/bid/101197
- https://access.redhat.com/errata/RHSA-2017:3463
- https://access.redhat.com/errata/RHSA-2018:0878
- https://github.com/golang/go/issues/22134
- https://golang.org/cl/68023
- https://golang.org/cl/68210
- https://groups.google.com/d/msg/golang-dev/RinSE3EiJBI/kYL7zb07AgAJ
- https://security.gentoo.org/glsa/201710-23
- http://www.securityfocus.com/bid/101197
- https://access.redhat.com/errata/RHSA-2017:3463
- https://access.redhat.com/errata/RHSA-2018:0878
- https://github.com/golang/go/issues/22134
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