How severe is CVE-2026-23845?

CVE-2026-23845 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-23845 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23845?

CVE-2026-23845 affects Axllent Mailpit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23845?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-23845 have an EU (EUVD) identifier?

Yes. CVE-2026-23845 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3296.

When was CVE-2026-23845 published?

CVE-2026-23845 was published on 2026-01-19 and last updated on 2026-06-17.

CVE-2026-23845

CVE-2026-23845 is a medium-severity vulnerability in Axllent Mailpit with a CVSS 3.x base score of 5.8. 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-918.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3296
Weakness: CWE-918
Affected product: Axllent Mailpit
Published: 2026-01-19
Last modified: 2026-06-17

Description

Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (`/api/v1/message/{ID}/html-check`) is designed to analyze HTML emails for compatibility. During this process, the `inlineRemoteCSS()` function automatically downloads CSS files from external `<link rel="stylesheet" href="...">` tags to inline them for testing. Version 1.28.3 fixes the issue.

Frequently asked questions

What is CVE-2026-23845?: Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (`/api/v1/message/{ID}/html-check`) is designed to analyze HTML emails for compatibility. During this process, the `inlineRemoteCSS()` function automatically downloads CSS files from external `<link rel="stylesheet" href="...">` tags to inline them for testing. Version 1.28.3 fixes the issue.
How severe is CVE-2026-23845?: CVE-2026-23845 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-23845 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23845?: CVE-2026-23845 affects Axllent Mailpit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23845?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23845 have an EU (EUVD) identifier?: Yes. CVE-2026-23845 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3296.
When was CVE-2026-23845 published?: CVE-2026-23845 was published on 2026-01-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*

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