Nodemailer before 9.1.0 Email Domain Validation Bypass via RFC 5322 Comment
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
Nodemailer versions >= 6.9.16 and < 9.1.0 mis-parse RFC 5322 comments in email addresses: in lib/addressparser, a comment closed immediately before a non-break character causes the tokenizer to concatenate the atoms surrounding the comment instead of treating the comment as folding whitespace that terminates the domain. A recipient address such as [email protected](x)evil.com is therefore read by Nodemailer as the single domain good-corp.comevil.com (registrable domain comevil.com, which an attacker can register) and used for both the SMTP envelope (RCPT TO) and the emitted To:/From: headers, while a conformant RFC 5322 parser terminates the domain at the comment and reads good-corp.com. An application that validates the recipient domain with a strict RFC 5322 parser (without inspecting parse defects) or a naive prefix/substring allow-list and then hands the raw address to Nodemailer can be induced to deliver mail to a domain the attacker controls. Fixed in 9.1.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| nodemailer | nodemailer | 6.9.16 to before 9.1.0 | 9.1.0 | Patch available | CNA |
- nodemailer Vendornodemailer Affected 6.9.16 to before 9.1.0 Fixed in 9.1.0 Patch available CNA
Remediation
- Fix · CNA nodemailer (nodemailer) Fixed in 9.1.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
nodemailer 9.1.0
3 records Highest priority Priority HIGH 2 HIGH, 1 LOW
Other records, highest priority first
- TI-2026-62452 Nodemailer before 9.1.0 Denial of Service via addressparserPriority HIGH 77
- TI-2026-62454 Nodemailer before 9.1.0 IDN/Punycode Domain Allow-list BypassPriority HIGH 69
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Self-service automation portal 2 | Affected | No fix yet |
Not affected: 3 products
- Red Hat Developer Hub 1
- Red Hat Enterprise Linux 10
- Red Hat Hardened Images
Timeline
- 2026-10-02 Threatist record created from CVE-2026-92597
- 2026-10-03 Alias added: GHSA-8pjj-q6q6-qm29
- 2026-10-27 Affected versions changed · Red Hat
References
Patch 1
More nodemailer vulnerabilities
- TI-2026-74559 ReDoS in Nodemailer SMTP AUTH mechanism detection regexes CVSS 4.0HIGH 8.7
- TI-2026-64856 nodemailer before 10.0.6 Denial of Service via addressparser CVSS 4.0HIGH 8.7
- TI-2026-62452 Nodemailer before 9.1.0 Denial of Service via addressparser CVSS 4.0HIGH 8.7
- TI-2026-61683 Nodemailer 9.1.0 through 10.0.4 Denial of Service via Quadratic Address Parsing CVSS 4.0HIGH 8.7
- TI-2025-13566 Nodemailer: nodemailer: denial of service via crafted email address header CVSS 3.1HIGH 7.5
- TI-2026-74560 Nodemailer address parser passes illegal characters to SMTP envelope CVSS 4.0MEDIUM 6.9
Sources
- CVE-2026-92597 · CVE Program
- CVE-2026-92597 · NVD
- FIRST EPSS
- GHSA-8pjj-q6q6-qm29 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-92597 · Red Hat security data · CC BY 4.0
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