| Título | The Trusted Domain Project OpenDMARC 1.4.2 Improper Authentication |
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| Descrição | OpenDMARC 1.4.2 fails to normalize certain Unicode characters in the domain of the visible `From:` address before performing a DMARC policy lookup. A crafted domain containing a Unicode character that maps to an ASCII domain separator, such as a fullwidth full stop, may therefore be treated as a different and policy-less domain. OpenDMARC returns `dmarc=none` instead of applying the DMARC policy published for the corresponding ASCII domain.
A remote unauthenticated attacker can exploit this issue by sending a forged message whose `From:` domain visually resembles a protected domain but uses such a Unicode character. No signing key or control of the victim’s DNS records is required. As a result, a published `p=reject` or `p=quarantine` policy may be bypassed, increasing the risk of email impersonation and phishing. |
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| Fonte | ⚠️ https://weitongli.com/share/opendmarc-unicode-dot-bypass.html |
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| Utilizador | WeitongLi (UID 100239) |
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| Submissão | 06/08/2026 12h53 (há 2 meses) |
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| Moderação | 27/09/2026 13h33 (2 months later) |
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| Estado | Aceite |
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| Entrada VulDB | 410885 [Trusted Domain Project OpenDMARC até 1.4.2 policy.c Execução remota de código] |
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| Pontos | 20 |
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