CVE-2025-59937

CVE-2025-59937 is a critical-severity vulnerability in Pebcak Go-mail with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-88.

Key facts

Description

go-mail is a comprehensive library for sending mails with Go. In versions 0.7.0 and below, due to incorrect handling of the mail.Address values when a sender- or recipient address is passed to the corresponding MAIL FROM or RCPT TO commands of the SMTP client, there is a possibility of wrong address routing or even ESMTP parameter smuggling. For successful exploitation, it is required that the user's code allows for arbitrary mail address input (i. e. through a web form or similar). If only static mail addresses are used (i. e. in a config file) and the mail addresses in use do not consist of quoted local parts, this should not affect users. This issue is fixed in version 0.7.1

Frequently asked questions

What is CVE-2025-59937?
go-mail is a comprehensive library for sending mails with Go. In versions 0.7.0 and below, due to incorrect handling of the mail.Address values when a sender- or recipient address is passed to the corresponding MAIL FROM or RCPT TO commands of the SMTP client, there is a possibility of wrong address routing or even ESMTP parameter smuggling. For successful exploitation, it is required that the user's code allows for arbitrary mail address input (i. e. through a web form or similar). If only static mail addresses are used (i. e. in a config file) and the mail addresses in use do not consist of quoted local parts, this should not affect users. This issue is fixed in version 0.7.1
How severe is CVE-2025-59937?
CVE-2025-59937 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-59937 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-59937?
CVE-2025-59937 affects Pebcak Go-mail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-59937?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-59937 have an EU (EUVD) identifier?
Yes. CVE-2025-59937 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31582.
When was CVE-2025-59937 published?
CVE-2025-59937 was published on 2025-09-29 and last updated on 2026-06-17.

References

Affected products (1)

Other CWE-88 (Argument Injection) vulnerabilities

Browse all CWE-88 (Argument Injection) vulnerabilities →