Home/CVE/When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentica
CVE

CVE-2025-59028

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentica

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments).

No publicly available exploits are known.

MEDIUM · CVSS 5.3 EPSS 0.0009
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-20Improper Input Validation
▤

Affected Products & Versions

2
dovecot< 2.4.3
open-xchange dovecot< 3.1.2
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · security@open-xchange.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD27 Mar 2026 · 09:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

4
suse-csafopenSUSE-SU-2026:20554-1
suse-csafSUSE-SU-2026:21208-1
usnUSN-8136-1
suse-csafopenSUSE-SU-2026:10442-1
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.jsonVendor Advisory
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