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Vulnerabilities

Vulnerability · CVE-2025-59045

Stalwart is a mail and collaboration server.

Published Sep 10, 2025 · catalog updated Sep 11, 2025 · Stalwart is a mail

Last checked Oct 23, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-59045. EPSS is 0.35%. 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.
Severity
High7.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Version ranges on file
Affected products
vendor stalwartlabs stalwart 0.12.0, < 0.13.3

Stalwart is a mail and collaboration server. Starting in version 0.12.0 and prior to version 0.13.3, a memory exhaustion vulnerability exists in Stalwart's CalDAV implementation that allows authenticated attackers to cause denial-of-service by triggering unbounded memory consumption through recurring event expansion. An authenticated attacker can crash the Stalwart server by creating recurring events with large payloads and triggering their expansion through CalDAV REPORT requests. A single malicious request expanding 300 events with 1000-character descriptions can consume up to 2 GB of memory

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 0.12.0, < 0.13.30.12.0, < 0.13.3

How to fix CVE-2025-59045

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-2025-59045. EPSS is 0.35%. 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 0.12.0, < 0.13.3 0.12.0, < 0.13.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.35%. 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. Sep 10, 2025 · EUVD

    Detected

    Stalwart is a mail and collaboration server. Starting in version 0.12.0 and prior to version 0.13.3, a memory exhaustion vulnerability exists in Stalwart's CalDAV implementation that allows authenticated attackers to cause denial-of-service by triggering unbounded memory consumption through recurring event expansion. An authenticated attacker can crash the Stalwart server by creating recurring eve

  2. Sep 11, 2025 · EUVD

    Updated

    Stalwart is a mail and collaboration server. Starting in version 0.12.0 and prior to version 0.13.3, a memory exhaustion vulnerability exists in Stalwart's CalDAV implementation that allows authenticated attackers to cause denial-of-service by triggering unbounded memory consumption through recurring event expansion. An authenticated attacker can crash the Stalwart server by creating recurring eve

Sources

  • CVE.orgVulnerability recordCVE-2025-59045

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-59045

    30-day exploitation probability 0.35%

    first.org
  • EUVDVulnerability recordEUVD-2025-27571

    Stalwart is a mail and collaboration server. Starting in version 0.12.0 and prior to version 0.13.3, a memory exhaustion vulnerability exists in Stalwart's CalDAV implementation that allows authenticated attackers to cause denial-of-service by triggering unbounded memory consumpt

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 22, 2026
  • EUVDOct 22, 2026