How severe is CVE-2026-25529?

CVE-2026-25529 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-25529 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25529?

CVE-2026-25529 affects Postalserver Postal. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25529?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-25529 have an EU (EUVD) identifier?

Yes. CVE-2026-25529 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11603.

When was CVE-2026-25529 published?

CVE-2026-25529 was published on 2026-03-12 and last updated on 2026-06-17.

CVE-2026-25529

CVE-2026-25529 is a high-severity vulnerability in Postalserver Postal with a CVSS 3.x base score of 8.1. 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11603
Weakness: CWE-79
Affected product: Postalserver Postal
Published: 2026-03-12
Last modified: 2026-06-17

Description

Postal is an open source SMTP server. Postal versions less than 3.3.5 had a HTML injection vulnerability that allowed unescaped data to be included in the admin interface. The primary way for unescaped data to be added is via the API's "send/raw" method. This could allow arbitrary HTML to be injected in to the page which may modify the page in a misleading way or allow for unauthorised javascript to be executed. Fixed in 3.3.5 and higher.

Frequently asked questions

What is CVE-2026-25529?: Postal is an open source SMTP server. Postal versions less than 3.3.5 had a HTML injection vulnerability that allowed unescaped data to be included in the admin interface. The primary way for unescaped data to be added is via the API's "send/raw" method. This could allow arbitrary HTML to be injected in to the page which may modify the page in a misleading way or allow for unauthorised javascript to be executed. Fixed in 3.3.5 and higher.
How severe is CVE-2026-25529?: CVE-2026-25529 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-25529 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25529?: CVE-2026-25529 affects Postalserver Postal. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25529?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-25529 have an EU (EUVD) identifier?: Yes. CVE-2026-25529 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11603.
When was CVE-2026-25529 published?: CVE-2026-25529 was published on 2026-03-12 and last updated on 2026-06-17.

References

https://github.com/postalserver/postal/security/advisories/GHSA-5f4r-5jpr-rfhc

Affected products (1)

cpe:2.3:a:postalserver:postal:*:*:*:*:*:*:*:*

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