How severe is GHSA-wpwj-69cm-q9c5?

No CVSS score has been assigned to GHSA-wpwj-69cm-q9c5 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-wpwj-69cm-q9c5?

GHSA-wpwj-69cm-q9c5 affects the following packages: github.com/wneessen/go-mail (Go). Ecosystems affected: Go.

How do I fix GHSA-wpwj-69cm-q9c5?

Update github.com/wneessen/go-mail to 0.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wpwj-69cm-q9c5 is resolved across your whole dependency graph.

How do I detect GHSA-wpwj-69cm-q9c5 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/wneessen/go-mail. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-wpwj-69cm-q9c5 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-wpwj-69cm-q9c5?

O3 pinpoints whether GHSA-wpwj-69cm-q9c5 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-wpwj-69cm-q9c5 actively exploited in the wild?

No public exploit code has been indexed for GHSA-wpwj-69cm-q9c5 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-wpwj-69cm-q9c5?

GHSA-wpwj-69cm-q9c5 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 38th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-wpwj-69cm-q9c5?

GHSA-wpwj-69cm-q9c5 is classified as CWE-88 (CWE-88). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-wpwj-69cm-q9c5 published, and has it been updated?

GHSA-wpwj-69cm-q9c5 was published on September 29, 2025 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-wpwj-69cm-q9c5

go-mail has insufficient address encoding when passing mail addresses to the SMTP client

Also known asCVE-2025-59937GO-2025-3988

Published

Sep 29, 2025

Updated

Feb 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk38th percentile+0.42%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐹github.com/wneessen/go-mail

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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, this could lead to a possible wrong address routing or even to ESMTP parameter smuggling.

Vulnerability details

Instead of making use of the String() method of mail.Address, which takes care of proper escaping and quotation of mail address, we used the Address value of the mail.Address which is the raw value when passing it to our SMTP client.

This meant, if a mail address like this was set: "[email protected]> [email protected]"@example.com for a sender or recipient, instead of the correctly quoted/escaped address, the SMTP client would get the raw value passed which would translate into something like this being passed to the SMTP server: RCPT TO:<[email protected]> [email protected]@example.com>.

Since ORCTP is a valid command for the SMTP server, the mail would be routed to the wrong address. Additionally, other SMTP commands could potientially be smuggled in using this method causing unexpected behaviour.

Exploitation requirements

For successful exploitation of this vulnerability it is required that the user's code is allowing 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 your code.

Patches

The vulnerability has been fixed with PR #496 and the fix has been shipped with the go-mail v0.7.1 release.

Issue #495 holds the full report and discussion.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/wneessen/go-mail`	all versions	0.7.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/wneessen/go-mail. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/wneessen/go-mail to 0.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wpwj-69cm-q9c5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-wpwj-69cm-q9c5 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-wpwj-69cm-q9c5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact 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, this could lead to a possible wrong address routing or even to ESMTP parameter smuggling. #### Vulnerability details Instead of making use of the `String()` method of `mail.Address`, which takes care of proper escaping and quotation of mail address, we used the `Address` value of the `mail.Address` which is the raw value when passing it to our SMTP client. This meant, if a mail address like this was set: `"t

O3 Security · Impact-Aware SCA

Is GHSA-wpwj-69cm-q9c5 in your dependencies?

O3 detects GHSA-wpwj-69cm-q9c5 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works