CVE-2023-5770
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 · uneditedProofpoint Enterprise Protection contains a vulnerability in the email delivery agent that allows an unauthenticated attacker to inject improperly encoded HTML into the email body of a message through the email subject. The vulnerability is caused by inappropriate encoding when rewriting the email before delivery.This issue affects Proofpoint Enterprise Protection: from 8.20.2 before patch 4809, from 8.20.0 before patch 4805, from 8.18.6 before patch 4804 and all other prior versions.
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 · high confidenceProofpoint Enterprise Protection has an HTML injection vulnerability in its email delivery agent. An unauthenticated attacker can inject improperly encoded HTML into email bodies by including malicious HTML markup in the email subject line. The email rewriting process fails to properly encode subject content before inserting it into the message body, allowing stored XSS or HTML injection.
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= 8.18.6= 8.20.0= 8.20.2CVSS 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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Identify installed Proofpoint Enterprise Protection versionUse the product's administrative interface or run the version check command provided in the product documentation to retrieve the exact installed version numberAffected if The installed version is 8.18.6, 8.20.0, or 8.20.2 exactly, or if the version cannot be determined and falls within any 8.x release line prior to patching
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Verify email delivery agent component is activeConfirm through the Proofpoint administrative console or service status command that the email delivery agent service is running and processing email trafficAffected if The email delivery agent is enabled and actively processing incoming email messages through the system
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Confirm email rewriting processing is enabledCheck the email processing configuration settings to verify that the subject line rewriting or insertion into message body feature is enabledAffected if Email subject line content is being rewritten or inserted into email bodies without proper HTML encoding
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Inspect email logs for suspicious subject line contentReview email gateway logs for entries containing raw HTML markup, script tags, or unusual HTML elements in subject line fields that may indicate exploitation attemptsAffected if Log entries show unencoded HTML or script tags present in subject line fields being processed by the system
A user is affected if they are running Proofpoint Enterprise Protection version 8.18.6, 8.20.0, or 8.20.2 with the email delivery agent enabled and subject line rewriting active, as the lack of HTML encoding during email processing creates the 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.
dbcve · scopedApply the appropriate patch for the installed version: patch 4809 for 8.20.2, patch 4805 for 8.20.0, or patch 4804 for 8.18.6. For all prior versions, upgrade to a supported version and apply the latest patch.
- Identify the current installed version of Proofpoint Enterprise Protection
- For version 8.18.6: apply patch 4804
- For version 8.20.0: apply patch 4805
- For version 8.20.2: apply patch 4809
- Verify the patch was applied successfully by checking the patch level in the system administration console
- Confirm the vulnerability is resolved by testing email subject line encoding
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-5770 — 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-2023-5770 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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- 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