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HIGH

CVE-2026-110869

CVSS v3

7.5

HIGH

EPSS Score

0.3 %

exploit probability, as of 2026-10-16

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-110869 Red Hat Product Security5 known affected

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

    rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub · grafana as a component of Red Hat Enterprise Linux 10 · grafana-selinux as a component of Red Hat Enterprise Linux 10

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-10-14
Last Modified
2026-10-15

Frequently asked questions

What is CVE-2026-110869?

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.

Is CVE-2026-110869 actively exploited?

Active exploitation of CVE-2026-110869 has not been confirmed. Its EPSS score was 0.3% on 2026-10-16, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-110869?

CVE-2026-110869 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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