CVE-2026-21409VulnerabilityPublished 9 Jan 2026

CVE-2026-21409: RICOH Streamline NX · Insecure Direct Object Reference

Affects RICOH Streamline NXSource CVE Database V5

Not known to be exploited · CVSS 5.9 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.0 base score

5.9Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
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: 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: None: The vulnerable system can be exploited without any interaction from any user.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within 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 9 Jan 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
Ricoh Company, Ltd.RICOH Streamline NX	Affected =3.5.1 to 24R3	Fixed in–

AI-suggested

1. Apply any available patches or updates from Ricoh as soon as they are released to address this vulnerability. 2. Enforce the use of strong encryption protocols (e.g., TLS 1.2 or higher) for all communications between clients and Ricoh Streamline NX servers to prevent man-in-the-middle attacks. 3. Implement network segmentation and strict firewall rules to limit access to Ricoh Streamline NX servers only to trusted internal networks and VPN users. 4. Monitor network traffic for unusual patterns that could indicate interception or manipulation attempts, such as unexpected requests or anomalous token usage. 5. Review and harden OIDC token handling and storage policies, ensuring tokens have short lifetimes and are securely stored. 6. Educate IT and security teams about the risks of man-in-the-middle attacks and the importance of secure communication channels. 7. Consider deploying network intrusion detection/prevention systems (IDS/IPS) capable of detecting MitM attempts. 8. Conduct regular security assessments and penetration tests focusing on network security and authentication flows involving Ricoh Streamline NX. 9. If possible, use multi-factor authentication (MFA) for accessing systems integrated with OIDC tokens to reduce the impact of token compromise. 10. Maintain an incident response plan that includes steps for token compromise and unauthorized access scenarios.

Description

CVE-2026-21409 is an authorization bypass vulnerability in Ricoh Streamline NX versions 3.5.1 through 24R3. The flaw allows a man-in-the-middle attacker to intercept communications and craft requests that can retrieve user registration information and OpenID Connect (OIDC) tokens. This vulnerability does not require user interaction or authentication but does require the attacker to be positioned to intercept network traffic. The CVSS score is 5.9 (medium severity) due to the high impact on confidentiality but no impact on integrity or availability. Exploitation could lead to unauthorized access to sensitive user identity tokens, potentially enabling further impersonation or access escalation. No known exploits are currently reported in the wild. European organizations using affected Ricoh Streamline NX versions are at risk, especially those with sensitive document workflows relying on OIDC authentication.

Impact

For European organizations, the impact of CVE-2026-21409 can be significant, particularly for those handling sensitive documents and relying on Ricoh Streamline NX for document workflow and identity management. Exposure of user registration data and OIDC tokens can lead to unauthorized access to internal systems, identity theft, and potential lateral movement within networks. Confidentiality breaches could compromise personal data protected under GDPR, leading to regulatory penalties and reputational damage. Since the vulnerability requires a man-in-the-middle position, organizations with insufficient network segmentation or lacking encrypted communication channels are at higher risk. The compromise of OIDC tokens could also undermine single sign-on (SSO) systems, affecting multiple connected applications. This vulnerability may particularly affect sectors such as government, finance, healthcare, and legal services, where document confidentiality and identity assurance are critical. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability is publicly known.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Jan 2026, 10:07 UTC

Technical details

References

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