CVE-2026-110869
ReDoS in Nodemailer SMTP AUTH regexes can block Node.js event loop.
Is CVE-2026-110869 being exploited?
Not confirmed. CVE-2026-110869 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-110869?
CVE-2026-110869 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-110869?
Yes. A fix has been recorded for CVE-2026-110869. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-110869 affect?
CVE-2026-110869 affects Nodemailer < 10.0.13, Node.js apps using Nodemailer SMTP transport, Email-sending services built on Nodemailer. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-110869?
Upgrade Nodemailer to >=10.0.13 and restrict/validate SMTP servers; add timeouts/rate limits.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malicious or MITM SMTP server can trigger regex backtracking on EHLO, blocking Node.js event loop for seconds–hours, causing denial of service and auth failures.
Immediate action required
- affected>= 3.0.0 and < 10.0.13
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.