What’s Vulnerable › Vulnerabilities

CVE-2026-42507: Arbitrary inputs are included in errors without any escaping in net/textproto

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-02 · updated 2026-07-22

Description

When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.

Affected products

• Go Stdlib: before 1.25.11; from 1.26.0-0 before 1.26.4 — fixed in 1.25.11, 1.26.4
• Go standard library net/textproto: before 1.25.11; from 1.26.0-0 before 1.26.4 — fixed in 1.25.11, 1.26.4

How to fix

Upgrade to a fixed version: Go Stdlib 1.25.11, 1.26.4; Go standard library net/textproto 1.25.11, 1.26.4. Check the vendor advisory for mitigations.

References

• https://go.dev/cl/777060
• https://go.dev/issue/79346
• https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw
• https://pkg.go.dev/vuln/GO-2026-5039

Get alerted when CVE-2026-42507 or the next vulnerability affects your stack