CVE-2026-45713: Mailpit is an email testing tool and API for developers

Q: How do I fix CVE-2026-45713?

mailpit: upgrade to 1.30.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-45713 being exploited?

CVE-2026-45713 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-45713 affect?

CVE-2026-45713 affects mailpit. Severity is high (CVSS 7.5). Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the Mailpit SMTP server has a Server.MaxSize int field that controls the maximum allowed DATA payload size, but the field is never assigned anywhere outside t

Q: How urgent is CVE-2026-45713?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-45713 is a high-severity flaw (CVSS 7.5) affecting mailpit. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the Mailpit SMTP server has a Server.MaxSize int field that controls the maximum allowed DATA payload size, but the field is never assigned anywhere outside test code, leaving it at Go's zero value (0 ⇒ "no limit"). The same applies to the HTTP /api/v1/send endpoint, whose request body is decoded with json.NewDecoder(r.Body) and no http.MaxBytesReader. Because Mailp

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-400, CWE-770
Published	2026-07-20
Last modified	2026-10-24

Publisher (CNA): GitHub, Inc. · Vendor: axllent

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-20 16:17 UTCPublished CVE record published
2026-10-24 20:10 UTCUpdated Record last modified

axllent mailpit UPGRADE

Affected: < 1.30.0

Fixed in: 1.30.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mailpit || rpm -q mailpit || mailpit --version

2. UPGRADE to 1.30.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mailpit

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mailpit

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45713?

mailpit: upgrade to 1.30.0. Exact commands for each OS are on this page.

Is CVE-2026-45713 being exploited?

CVE-2026-45713 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45713 affect?

CVE-2026-45713 affects mailpit. Severity is high (CVSS 7.5). Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the Mailpit SMTP server has a Server.MaxSize int field that controls the maximum allowed DATA payload size, but the field is never assigned anywhere outside t

How urgent is CVE-2026-45713?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-48824 MEDIUM 5.3 UPGRADE Mailpit is an email testing tool and API for developers
CVE-2026-45712 MEDIUM 5.9 UPGRADE Mailpit is an email testing tool and API for developers
CVE-2026-45709 MEDIUM 5.8 UPGRADE Mailpit is an email testing tool and API for developers
CVE-2026-45711 MEDIUM 5.9 UPGRADE Mailpit is an email testing tool and API for developers

References

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