nodemailer before 10.0.6 contains a denial of service vulnerability in the addressparser free-text fallback regex pattern that exhibits quadratic… (CVE-2026-100700)
Nodemailer versions before 10.0.6 have a denial of service vulnerability due to a regex pattern in the addressparser free-text fallback that causes quadratic backtracking. This can be exploited by attackers supplying crafted email header values with long whitespace-free runs, blocking the Node.js event loop and causing service unavailability.
AI Analysis
Technical Summary
The vulnerability in nodemailer before version 10.0.6 involves the addressparser module's free-text fallback regex pattern exhibiting quadratic backtracking behavior. This flaw allows an attacker to craft email header values containing long sequences without whitespace, which triggers excessive regex processing time. As a result, the Node.js event loop can be blocked for tens of seconds, leading to a denial of service condition where the service becomes unavailable.
Potential Impact
An attacker can cause denial of service by sending specially crafted email headers that exploit the regex backtracking issue, blocking the Node.js event loop and rendering the service unresponsive for extended periods. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Upgrade nodemailer to version 10.0.6 or later where this vulnerability is fixed. Since the vulnerability is patched in 10.0.6, applying this official fix will mitigate the issue.
nodemailer before 10.0.6 contains a denial of service vulnerability in the addressparser free-text fallback regex pattern that exhibits quadratic… (CVE-2026-100700)
Description
Nodemailer versions before 10.0.6 have a denial of service vulnerability due to a regex pattern in the addressparser free-text fallback that causes quadratic backtracking. This can be exploited by attackers supplying crafted email header values with long whitespace-free runs, blocking the Node.js event loop and causing service unavailability.
CVSS v3.1
Score 7.5high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in nodemailer before version 10.0.6 involves the addressparser module's free-text fallback regex pattern exhibiting quadratic backtracking behavior. This flaw allows an attacker to craft email header values containing long sequences without whitespace, which triggers excessive regex processing time. As a result, the Node.js event loop can be blocked for tens of seconds, leading to a denial of service condition where the service becomes unavailable.
Potential Impact
An attacker can cause denial of service by sending specially crafted email headers that exploit the regex backtracking issue, blocking the Node.js event loop and rendering the service unresponsive for extended periods. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Upgrade nodemailer to version 10.0.6 or later where this vulnerability is fixed. Since the vulnerability is patched in 10.0.6, applying this official fix will mitigate the issue.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-c7vw-frhj-6h9j
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-100700"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6ab89bd9f7a7c54106942021
Added to database: 09/27/2026, 04:30:17 UTC
Last enriched: 09/27/2026, 04:41:39 UTC
Last updated: 09/28/2026, 02:52:57 UTC
Views: 19
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.