VulnerabilityPublished 22 Mar 2026Updated 23 Mar 2026

CVE-2026-33550: Alinto SOGo · Use of Single-factor Authentication

Affects Alinto SOGoSource CVE Database V5

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Not known to be exploited · CVSS 2.0 Low : upgrade to 5.12.5 when convenient.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score

2.0Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.12.5

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: High
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade SOGo and alinto/sogo to 5.12.5.

Affected software

Product	Affected	Fixed in
AlintoSOGo	Affected <5.12.5	Fixed in 5.12.5
GitHubalinto/sogo`pkg:github/alinto/sogo`Other threats	Affected <5.12.5	Fixed in 5.12.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should upgrade Alinto SOGo to version 5.12.5 or later, where this vulnerability is addressed. Administrators must ensure that OTP secrets are properly renewed whenever users disable and re-enable MFA to prevent reuse of old OTP secrets. Increasing the OTP length to at least the recommended 20 digits will significantly enhance the security of the second factor. Additionally, organizations should audit their MFA configurations to verify compliance with best practices, including enforcing strong OTP generation parameters and monitoring for unusual authentication patterns. User education on the importance of MFA and cautious handling of authentication settings can further reduce risk. Implementing additional layers of security such as device-based authentication or hardware tokens may also help mitigate risks associated with weak OTP implementations.

Description

CVE-2026-33550 is a low-severity vulnerability in Alinto's SOGo email and collaboration platform versions before 5.12.5. The issue involves improper handling of one-time passwords (OTPs) used for multi-factor authentication (MFA). Specifically, when a user disables and then re-enables OTP-based MFA, the system fails to renew the OTP secret, and the OTP length is only 12 digits instead of the recommended 20 digits. This weakness effectively reduces the strength of the second authentication factor, increasing the risk of unauthorized access through OTP guessing or replay attacks. Exploitation requires high privileges and user interaction, and no known exploits exist in the wild. Organizations using vulnerable SOGo versions should upgrade to 5.12.5 or later and enforce stronger OTP configurations to mitigate this risk.

Impact

The primary impact of this vulnerability is a reduction in the security strength of the multi-factor authentication mechanism in SOGo, potentially allowing attackers with sufficient privileges and user interaction to bypass or weaken the second authentication factor. This could lead to unauthorized access to user accounts, compromising the integrity of email and collaboration data. While confidentiality and availability are not directly affected, unauthorized account access can facilitate further attacks such as phishing, data manipulation, or lateral movement within an organization. The low CVSS score and lack of known exploits suggest limited immediate risk, but organizations relying on SOGo for secure communications could face increased risk if attackers exploit this weakness in OTP management. The impact is more pronounced in environments where SOGo is a critical communication platform and where MFA is relied upon heavily for securing user access.

Summary

CVE-2026-33550 addresses a security vulnerability in Alinto's SOGo collaboration suite prior to version 5.12.5, related to the implementation of OTP-based multi-factor authentication. The vulnerability arises because the system does not renew the OTP secret when a user disables and then re-enables OTP MFA, meaning the same OTP secret remains active. Additionally, the OTP length is limited to 12 digits, which is significantly shorter than the recommended 20-digit length for robust security. This combination weakens the second factor's effectiveness, potentially allowing attackers to guess or replay OTPs more easily. The vulnerability is classified under CWE-308, indicating the use of single-factor authentication or weak multi-factor authentication mechanisms. The CVSS v3.1 base score is 2.0, reflecting low severity due to the requirement of high privileges (PR:H), user interaction (UI:R), and high attack complexity (AC:H). The vulnerability does not impact confidentiality but can lead to integrity loss if an attacker successfully bypasses MFA. No known exploits have been reported, and no patches are explicitly linked, but upgrading to version 5.12.5 or later is advised. This vulnerability highlights the importance of proper OTP lifecycle management and adherence to recommended OTP length standards to maintain strong authentication security.

CWE-308Use of Single-factor Authentication (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product uses an authentication algorithm that uses a single factor (e.g., a password) in a security context that should require more than one factor.
Architecture and Design
Use multiple independent authentication schemes, which ensures that -- if one of the methods is compromised -- the system itself is still likely safe from compromise. For this reason, if multiple schemes are possible, they should be implemented and required -- especially if they are easy to use.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.7 (opens in a new tab)
V2.6.1 (opens in a new tab)
V2.3.2 (opens in a new tab)
Attack patterns
Dictionary-based Password Attack (opens in a new tab)
Password Brute Forcing (opens in a new tab)
Kerberoasting (opens in a new tab)
Rainbow Table Password Cracking (opens in a new tab)
Remote Services with Stolen Credentials (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Mar 2026, 20:10 UTC

WeaknessesCWE-308

Technical details

References

Community reviews

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