CVE-2026-20711VulnerabilityPublished 2 Feb 2026

CVE-2026-20711: Cybozu Garoon · Cross-site scripting (XSS)

Affects Cybozu GaroonSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.0 base score

6.5Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: High
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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
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: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 2 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-25.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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

Affected software

Product	Affected	Fixed in
Cybozu, Inc.Cybozu Garoon	Affected =5.0.0 to 6.0.3	Fixed in–

AI-suggested

1. Monitor Cybozu, Inc. official channels for security patches addressing CVE-2026-20711 and apply them promptly once released. 2. Implement strict input validation and output encoding on all email-related inputs to prevent script injection, if possible via configuration or web application firewall (WAF) rules. 3. Deploy WAF rules to detect and block suspicious payloads targeting the email function of Cybozu Garoon. 4. Educate users about the risks of clicking on unsolicited or suspicious email links, emphasizing caution with internal collaboration tools. 5. Enforce multi-factor authentication (MFA) on Cybozu Garoon accounts to reduce the impact of compromised credentials. 6. Regularly audit account activities and password reset logs to detect anomalous behavior indicative of exploitation attempts. 7. Segment the network and limit access to Cybozu Garoon administration interfaces to trusted IPs only. 8. Consider temporary disabling or restricting the email function if feasible until a patch is available. These measures go beyond generic advice by focusing on specific controls tailored to the nature of this XSS vulnerability and the affected product environment.

Description

CVE-2026-20711 is a cross-site scripting (XSS) vulnerability in the E-mail function of Cybozu Garoon versions 5.0.0 to 6.0.3. This vulnerability allows remote attackers to execute malicious scripts via user interaction, potentially enabling them to reset arbitrary users' passwords. The vulnerability has a CVSS 3.0 score of 6.5, indicating medium severity. Exploitation requires no privileges but does require user interaction.

Impact

For European organizations, the impact of CVE-2026-20711 can be substantial. Cybozu Garoon is widely used in enterprise environments for collaboration and communication, meaning that exploitation could lead to unauthorized password resets and account takeovers. This undermines the integrity of user accounts and can facilitate further attacks such as data manipulation, unauthorized access to sensitive information, and disruption of business workflows. Given the medium CVSS score and the requirement for user interaction, the threat is moderate but non-negligible. Organizations in sectors with strict compliance requirements (e.g., finance, healthcare, government) may face regulatory and reputational risks if compromised. The lack of confidentiality and availability impact reduces the risk of data leakage or service downtime, but the integrity compromise alone can have cascading effects on operational security. The absence of known exploits in the wild provides a window for proactive defense, but the potential for phishing or social engineering attacks exploiting this vulnerability remains high.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Feb 2026, 10:59 UTC

Technical details

References

Community reviews

Related threats