CVE-2026-92598VulnerabilityPublished 16 Sep 2026Updated 28 Oct 2026

Node nodemailer: Nodemailer before 9.1.0 fails to apply UTS-46 normalization when encoding international domain names

Affects node-nodemailerSource GCVE Database

Not known to be exploited · CVSS 6.5 Medium · fixed in 9.1.0 : update node-nodemailer when convenient.

Data as of 29 Oct 2026, 01:13 UTC

CVSS 3.1 base score

6.5Medium

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

Patch: Available – fixed in 9.1.0

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
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: 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: 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 16 Sep 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

Affected software

Product	Affected	Fixed in
Ubuntu 26.10node-nodemailer`pkg:deb/ubuntu/node-nodemailer?arch=source&distro=stonking`Other threats	Affected 8.0.4+~7.0.11-1 – 9.0.5+~8.0.1-1 5 affected builds	Fixed in–
Ubuntu 26.04 LTSnode-nodemailer`pkg:deb/ubuntu/node-nodemailer?arch=source&distro=resolute`Other threats	Affected 7.0.5+~7.0.1-1 – 8.0.4+~7.0.11-1 5 affected builds	Fixed in–
Ubuntu 24.04 LTSnode-nodemailer`pkg:deb/ubuntu/node-nodemailer?arch=source&distro=noble`Other threats	Affected =6.9.4+~6.4.9-2 =6.9.4+~6.4.9-3ubuntu1 =6.9.4+~6.4.9-4	Fixed in–
Ubuntu 22.04 LTSnode-nodemailer`pkg:deb/ubuntu/node-nodemailer?arch=source&distro=jammy`Other threats	Affected 6.4.17-3 – 6.7.1+~6.4.4-1 4 affected builds	Fixed in–
Ubuntu 20.04 LTSnode-nodemailer`pkg:deb/ubuntu/node-nodemailer?arch=source&distro=focal`Other threats	Affected 6.3.0-2 – 6.4.5-1 6 affected builds	Fixed in–

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

AI-suggested

Users should upgrade Nodemailer to version 9.1.0 or later, where this issue is fixed. Since the vulnerability is resolved in versions from 9.1.0 onward, applying this official fix is the recommended remediation. No vendor advisory or patch links were provided, so users should verify the fix availability in the official Nodemailer release notes or repository.

Description

Nodemailer versions before 9.1.0 do not correctly apply UTS-46 normalization when encoding internationalized domain names. This causes the domain resolver to compute a different Punycode A-label than standards-compliant parsers. As a result, attackers can craft recipient email addresses containing invisible characters or compatibility mappings that bypass domain allow-list checks but are delivered to attacker-controlled domains via SMTP.

Impact

This vulnerability allows attackers to bypass domain allow-list checks by exploiting differences in IDN normalization, potentially causing emails to be delivered to malicious domains. The impact includes possible unauthorized disclosure of sensitive information or phishing attacks due to misdirected emails. The CVSS score of 6.5 (medium severity) reflects a high confidentiality impact with limited integrity impact and no availability impact.

Summary

The vulnerability in Nodemailer prior to version 9.1.0 involves improper handling of internationalized domain names (IDNs). Specifically, the software fails to apply UTS-46 normalization during Punycode encoding, leading to discrepancies between the domain resolver's computed A-label and that of standards-compliant parsers. This mismatch enables attackers to create recipient addresses that appear valid and pass domain allow-list filters but ultimately route emails to attacker-controlled domains, potentially facilitating phishing or interception attacks.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 01:13 UTC

Technical details

References

Community reviews

Related threats