CVE-2026-33586Authenticated SMTP Sender Address Forgery
Updated under an hour ago ()
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It affects OVHcloud. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Authenticated users are able to manipulate both the SMTP envelope “Envelope-from” and “From” fields when sending emails through OVH mail servers. Due to OVH's default SPF configuration, which commonly includes include:mx.ovh.com, any authenticated user with a valid OVH email account can send messages that appear to originate from any OVH-hosted domains using the default SPF record. Since the SPF policy explicitly authorizes OVH mail servers (mx.ovh.com) to send mail on behalf of these domains, forged messages successfully pass SPF validation despite not being authorized by the impersonated domain owner.
- CVSS
- 6.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N/E:A
- Weakness (CWE)
- CWE-1188, CWE-346, CWE-290
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- ENISA
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 7, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
OVHcloud OVHcloud ovhcloud:ovhcloud (from the name) | before 2026-07-20 | CNA record |
References
- https://docs.ovhcloud.com/en/guides/web-cloud/email-and-collaborative-solutions/troubleshooting/email-rejected-cross-domain-spoofing
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.