CVE-2026-45712

CVE-2026-45712 is a medium-severity vulnerability in Axllent Mailpit with a CVSS 3.x base score of 5.9. 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-362.

Key facts

Description

Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the screenshot/print proxy (/proxy?data=…) maintains a package-level assets map[string]MessageAssets cache, but reads the map without holding assetsMutex while a long-running cleanup goroutine and (re-entrant) CSS-rewriting code path concurrently write to it under the lock. When the unsynchronized read coincides with a synchronized write, Go's runtime raises fatal error: concurrent map read and map write — a runtime.throw that is not recoverable by http.Server's handler-panic recover. The whole Mailpit process exits, taking the SMTP, POP3 and HTTP listeners down with it. Version 1.30.0 contains a patch.

Frequently asked questions

What is CVE-2026-45712?
Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the screenshot/print proxy (/proxy?data=…) maintains a package-level assets map[string]MessageAssets cache, but reads the map without holding assetsMutex while a long-running cleanup goroutine and (re-entrant) CSS-rewriting code path concurrently write to it under the lock. When the unsynchronized read coincides with a synchronized write, Go's runtime raises fatal error: concurrent map read and map write — a runtime.throw that is not recoverable by http.Server's handler-panic recover. The whole Mailpit process exits, taking the SMTP, POP3 and HTTP listeners down with it. Version 1.30.0 contains a patch.
How severe is CVE-2026-45712?
CVE-2026-45712 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-45712 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-45712?
CVE-2026-45712 affects Axllent Mailpit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-45712?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-45712 published?
CVE-2026-45712 was published on 2026-07-20 and last updated on 2026-07-28.

References

Affected products (1)

More vulnerabilities in Axllent Mailpit

All CVEs affecting Axllent Mailpit →

Other CWE-362 (Race Condition) vulnerabilities

Browse all CWE-362 (Race Condition) vulnerabilities →