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Fencer Vulns
high 7.5

CVE-2026-110869 json

Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection Regexes

published 2026-10-14 25 d ago modified 2026-10-27 12 d ago also GHSA-4ffr-jq9g-5ffx , EUVD-2026-101752

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Nodemailer 3.0.0 before 10.0.13 has a regular expression denial of service in SMTPConnection._actionEHLO, whose four AUTH mechanism detection regexes contain overlapping whitespace sub-patterns that backtrack quadratically. A malicious or man-in-the-middle SMTP server can reply to EHLO with 250-AUTH, a long whitespace run and a non-matching token, blocking the Node.js event loop for tens of seconds to hours before authentication.

Patch / fix

  • npm nodemailer 10.0.13
  • nodemailer nodemailer 10.0.13
  • node-nodemailer Debian 14 10.0.13+~8.0.2-1

debian advisories DEBIAN-CVE-2026-110869

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-110869 updated cvss 7.5

nodemailer: nodemailer: Denial of Service via regular expression backtracking in SMTP authentication parsing

  • Red Hat Self-service automation portal 2 ansible-automation-platform/bootc-automation-portal-rhel9
    affected: workaround, no fix available
  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat Enterprise Linux 10 grafana 12.4.3-2.el10
    not affected: vulnerable code not present
  • Red Hat Hardened Images grafana13.1 13.1.7-0.1.hum1, grafana13.2 13.2.3-0.1.hum1, grafana12.4 12.4.12-0.4.hum1
    not affected: component not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
24 d ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm nodemailer
>=3.0.0, <10.0.13
10.0.13

Affected products

  • nodemailer nodemailer

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.