CVE-2026-82661Public exploitNetwork attack vectorHinoki check available

Arbitrary header injection via unsanitized list comments

Published Aug 31, 2026 · Updated Aug 31, 2026

CRLF injection in Nodemailer before 8.0.9 allows remote authenticated users to add arbitrary headers via list comment fields. The _getListHeaders function copies list..comment input into prepared List- values without removing CR or LF, bypassing ordinary header normalization before foldLines emits the message. Reachability requires a consuming application to expose a list comment field; injected headers can alter message metadata and downstream mail-client or filter behavior, but no recipient injection or code execution was demonstrated.

CVSS severity5.4
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

CRLF injection in Nodemailer before 8.0.9 allows remote authenticated users to add arbitrary headers via list comment fields. The _getListHeaders function copies list..comment input into prepared List- values without removing CR or LF, bypassing ordinary header normalization before foldLines emits the message. Reachability requires a consuming application to expose a list comment field; injected headers can alter message metadata and downstream mail-client or filter behavior, but no recipient injection or code execution was demonstrated.

The record

CVE
CVE-2026-82661
Published
Aug 31, 2026
Updated
Aug 31, 2026
Vendor
Nodemailer
Product
Nodemailer
Classifications
CWE-93
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <8.0.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nodemailer · Nodemailerversion=0 <8.0.9

Published CVSS scores

5.4GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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