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.
EPSS: 0.004 (28.0th percentile) — read the EPSS interpretation.
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.
Affected products
- Stalw Stalwart
- Stalwartlabs Stalwart — versions >= 0.13.0, < 0.15.5
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, 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.