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Vulnerabilities

Vulnerability · CVE-2026-26312

Stalwart is a mail and collaboration server.

Published Feb 19, 2026 · catalog updated Feb 20, 2026 · Stalwart is a mail

Last checked Nov 12, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-26312. EPSS is 0.41%. Act only if a listed version of Stalwart is a mail is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Stalwart is a mail).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.41%
Remediation
Version ranges on file
Affected products
vendor stalwartlabs stalwart 0.13.0, < 0.15.5

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 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 crate to produce cyclical references in its parsed representation, which Stalwart then follows indefinitely. Version 0.15.5 contains a patch.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor stalwartlabs stalwart 0.13.0, < 0.15.50.13.0, < 0.15.5

How to fix CVE-2026-26312

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-26312. EPSS is 0.41%. Act only if a listed version of Stalwart is a mail is installed.

Which versions are affected?

Compare what you have installed with stalwartlabs stalwart 0.13.0, < 0.15.5 0.13.0, < 0.15.5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.41%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 19, 2026 · EUVD

    Detected

    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 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 crate to prod

  2. Feb 20, 2026 · EUVD

    Updated

    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 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 crate to prod

Sources

  • CVE.orgVulnerability recordCVE-2026-26312

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-26312

    30-day exploitation probability 0.41%

    first.org
  • EUVDVulnerability recordEUVD-2026-8304

    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 MIME parts via IMAP or JMAP causes excessive CPU and memory consumpti

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 12, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 9, 2026
  • CVE.orgNov 9, 2026
  • EUVDNov 9, 2026