Authenticated users are able to manipulate both the SMTP envelope “Envelope-from” and “From”...
Summary
Vulnerability reported (CVE-2026-33586). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-33586 has been found.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2026-33586" on the vendor's site.
CVE-2026-33586 — CWE-290
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-290) has been reported.
Check the vendor advisory for the affected versions.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web docs.ovhcloud.com
- web nvd.nist.gov
- web github.com