DuoApplication · Cisco
CVE-2025-20258
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability in the self-service portal of Cisco Duo could allow an unauthenticated, remote attacker to inject arbitrary commands into emails that are sent by the service. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by injecting arbitrary commands into a portion of an email that is sent by the service. A successful exploit could allow the attacker to send emails that contain malicious content to unsuspecting users.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA command injection vulnerability in the Cisco Duo self-service portal allows unauthenticated remote attackers to inject arbitrary commands into email content sent by the service. The vulnerability stems from insufficient input validation on user-supplied data that gets incorporated into emails.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
DuoApplication
all versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Cisco Duo deploymentInventory your environment for Cisco Duo services - check installed applications, cloud service subscriptions, or infrastructure that includes Cisco Duo authentication or MFA componentsAffected if Cisco Duo is present in the environment and the self-service portal email feature is accessible
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Identify self-service portal accessibilityDetermine if the Cisco Duo self-service portal is exposed internally or externally - check network configuration, firewall rules, and authentication settings that control access to the portalAffected if The self-service portal is reachable by unauthenticated or low-privilege users
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Review email activity logsExamine Cisco Duo email logs or mail server logs for messages originating from the Duo service that contain unexpected characters, command-like syntax, or abnormal formatting in email body or headersAffected if Emails sent by Duo contain suspicious injection patterns or malformed content
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Check for anomalous outbound emailsInspect email queuing or sent items from systems running Duo services for any emails with unusual command syntax, unexpected script fragments, or content that differs from expected Duo notification templatesAffected if Outbound emails contain arbitrary command-like content not originating from legitimate Duo templates
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Assess portal exposure scopeDocument which user populations have access to the self-service portal email functionality - check user roles, group memberships, and authentication policies governing self-service email operationsAffected if Users without administrative privileges can access and send emails through the self-service portal
The environment is affected if Cisco Duo is deployed and its self-service portal email functionality is accessible to users, since all versions contain the command injection vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor-provided patches/updates for Cisco Duo when released; as an interim measure, assess and potentially restrict access to the self-service portal email functionality until the patch is applied.
Fix this in Duo
Scoped from the published advisory
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,152.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20258 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-20258 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data