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Back to active CVEs
High · CVSS 8.2CVE-2026-86009

Mailu: Domain managers can allow themselves to spoof on other hosted domains they should not controlCVE-2026-86009

Answer in brief

CVE-2026-86009 records a High severity (CVSS 8.2) vulnerability in Mailu: Domain managers can allow themselves to spoof on other hosted domains they should not control. The current sources do not mark it as known exploited. The current feed maps Mailu/Mailu (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 16, 2026Updated Oct 16, 2026Source checked Oct 16, 2026First seen by HOL Oct 16, 2026Material review Oct 16, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.2
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Mailu/Mailu (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Mailu/Mailugeneric<f05aeb8322e2f61096af6b089d61ba6f40587d96f05aeb8322e2f61096af6b089d61ba6f40587d96

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Mailu/Mailu.
  2. 2Review the reported fix. Update Mailu/Mailu to f05aeb8322e2f61096af6b089d61ba6f40587d96 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Oct 16, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 16, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 16, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
Upstream source description

Mailu is a mail server distributed as a set of Docker images. Prior to f05aeb8322e2f61096af6b089d61ba6f40587d96, domain managers can enable spoofing for hosted domains they do not control. A potentially malicious domain administrator enables spoofing for another hosted domain and can send emails that are authenticated with DKIM/SPF for domains they should not be able to. This vulnerability is addressed by f05aeb8322e2f61096af6b089d61ba6f40587d96.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Mailu domain managers can take over higher-privileged accountsSame mailu/mailu package
  • Incorrect authorization in the Arm Cortex-R82 MPU port in FreeRTOS-KernelAlso CWE-863
  • Open Zaak: /zaken/_zoek and /enkelvoudiginformatieobjecten/_zoek endpoints do not filter result lists based on authorizations linked to tokenAlso CWE-285
  • MariaDB: GRANT PROXY with empty password incorrectly checks grantor's privilegesAlso CWE-863
  • Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP Router Advertisement handlingSame generic ecosystem
  • Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP DNS resolverSame generic ecosystem

Record context

Vulnerability class
Privilege Escalation
EPSS
Not reported
CWE IDs
CWE-285, CWE-863
Source
CVE List V5
Source checked
Oct 16, 2026
References
4 linked sources
Open source record