Resource exhaustion in Stalw Stalwart
CVE-2026-26312
Stalwart is a mail and collaboration server. A denial-of-service vulnerability exists in Stalwart Mail Server versions 0.13.0 through 0.15.4 where accessing a specially crafted email containing malformed nested `message/rfc822` MIME parts via IMAP or JMAP causes excessive CPU and memory consumption, potentially leading to an out-of-memory condition and server crash. The malformed structure causes the `mail-parser` crate to produce cyclical references in its parsed representation, which Stalwart then follows indefinitely. Version 0.15.5 contains a patch.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (37.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001
Affected products
- Stalw Stalwart
- Stalwartlabs Stalwart — versions >= 0.13.0, < 0.15.5
Weakness classification (CWE)
References
- github.com/stalwartlabs/stalwart/security/advisories/GHSA-jm95-876q-c9gw (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-26312?
- CVE-2026-26312 is a medium-severity vulnerability in Stalw Stalwart, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-02-19.
- How severe is CVE-2026-26312?
- Medium severity. CVSS v3 base score is 6.5 out of 10.