CVE-2025-8419Network attack vectorHinoki check available

Unsolicited email via Unicode-to-CRLF SMTP injection

Published Aug 6, 2025 · Updated Aug 31, 2026

SMTP injection in Keycloak before 26.3.3 allows remote attackers to send a short unsolicited email through its configured SMTP server. Email-registration recipient handling passes a crafted Unicode local part whose low bytes form CRLF-delimited SMTP commands. The unauthenticated path requires registration and outbound SMTP; the 64-character local-part limit restricts the injected subject and body.

CVSS severity5.3
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

SMTP injection in Keycloak before 26.3.3 allows remote attackers to send a short unsolicited email through its configured SMTP server. Email-registration recipient handling passes a crafted Unicode local part whose low bytes form CRLF-delimited SMTP commands. The unauthenticated path requires registration and outbound SMTP; the 64-character local-part limit restricts the injected subject and body.

The record

CVE
CVE-2025-8419
Published
Aug 6, 2025
Updated
Aug 31, 2026
Vendor
389 Directory Server
Product
Red Hat build of Keycloak
Classifications
CWE-20, CWE-93
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 6, 2025CVE 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat build of KeycloakAffected versions are unavailable in this record.
Keycloak · Keycloakversion=0 <26.3.3

Published CVSS scores

5.3Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')

Public exploit references

No public exploit references are available in this record.

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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