CVE-2025-27218
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 · uneditedSitecore Experience Manager (XM) and Experience Platform (XP) 10.4 before KB1002844 allow remote code execution through insecure deserialization.
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 confidenceSitecore XM/XP 10.4 versions before KB1002844 contain an insecure deserialization vulnerability that allows authenticated remote attackers to execute arbitrary code on the affected server by supplying malicious serialized objects.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 Sitecore versionAccess the Sitecore Admin version page (e.g., /sitecore/admin/showversion.aspx) or check the Sitecore.Kernel.dll assembly version in the /bin directory. Compare the version number to the 10.4.x family and note the specific build.Affected if The installed version is Sitecore XP or XM 10.4.x and does not have KB1002844 applied (version shows as pre-patch or no KB patch is listed)
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Confirm Sitecore patch statusCheck the Sitecore installation for applied hotfixes. This can be done by reviewing the Sitecore patch information in the /sitecore/admin/showconfig.aspx page, looking for KB1002844 in the configuration, or checking the release notes/changelog if accessible.Affected if KB1002844 is not listed among the installed patches or the configuration does not show this specific hotfix applied
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Verify authentication is enforced on deserialization endpointsIdentify endpoints that handle serialized data (common paths include /sitecore services, .ashx handlers, or API endpoints that accept binary/serialized input). Use a tool like curl or browser to attempt access to these endpoints without credentials.Affected if Deserialization-handling endpoints are accessible without valid authentication or accept serialized objects without strict allowlist validation
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Check network exposure of Sitecore instanceDetermine if the Sitecore instance is directly exposed to the internet or accessible from untrusted networks. Review firewall rules, load balancer configurations, and IIS bindings to identify external access paths.Affected if The Sitecore instance is reachable from untrusted networks (internet-facing) without network-level access restrictions
A user is affected if they are running Sitecore XM/XP 10.4.x without KB1002844 applied AND the deserialization functionality is accessible to authenticated attackers over the network.
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 KB1002844 patch to update Sitecore to a fixed version. If immediate patching is not possible, restrict network access to the Sitecore instance and review deserialization allowlists.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-27218 — 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-2025-27218 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