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Sitecore Experience Remote Code Execution through Insecure Deserialization

Not in CISA KEVCVE-2025-53691CWE-502

Not confirmed exploited. 2 of 8 rule sources name it; Cloudflare blocks by default.

Edge rules
2/8
Our test
No exploit yet
CVSS
8.8
EPSS
1.6% Top 24%
Posts, 14d
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Published
2025-09-03
Deserialization of Untrusted Data vulnerability in Sitecore Experience Manager (XM), Sitecore Experience Platform (XP) allows Remote Code Execution (RCE).This issue affects Experience Manager (XM): from 9.0 through 9.3, from 10.0 through… More

Deserialization of Untrusted Data vulnerability in Sitecore Experience Manager (XM), Sitecore Experience Platform (XP) allows Remote Code Execution (RCE).This issue affects Experience Manager (XM): from 9.0 through 9.3, from 10.0 through 10.4; Experience Platform (XP): from 9.0 through 9.3, from 10.0 through 10.4.

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AI · answers from this page
Ask about CVE-2025-53691: who's covered, what to patch first, how vendors compare. I cite sources and won't help with attacks.

Workers AI (Llama 3.3). Can be wrong: check the cited source.

Severity, decoded

CVSS 3.1
High · 8.8 / 10

Exploitable over the network, with low privileges and no user interaction, leading to full loss of confidentiality, integrity and availability.

Over the internetAny user loginNo user actionWorks reliablyFull compromise
How the score is built8 metrics
  • Attack vectorAn attacker can reach it over the internet; no access to your network needed.
    Network
  • Attack complexityNo special conditions are needed; the attack works reliably.
    Low
  • Privileges requiredThe attacker needs an ordinary user account.
    Low
  • User interactionNo one has to click or open anything; the attack works on its own.
    None
  • ScopeThe damage stays within the vulnerable component.
    Unchanged
  • Confidentiality impactAn attacker can read all data the affected component holds, or the most sensitive parts of it.
    High
  • Integrity impactAn attacker can change any data or files the affected component protects.
    High
  • Availability impactAn attacker can take the component down completely or keep it from serving anyone.
    High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA's assessmentSSVC, from the CVE record
ExploitationProof of concept

Public exploit code or a detailed write-up exists, but CISA has not seen attacks.

AutomatableNo

At least one step needs hands-on work, which slows mass attacks.

Technical impactTotal

A successful attack gives full control over the affected software or all of its data.

Public exploits

None found
0 Metasploit0 Exploit-DB0 Scanner template0 GitHub PoCs

No exploit in Exploit-DB or Metasploit, and no scanner template. That lowers, but doesn't remove, the chance of mass exploitation.

Timeline

  1. 2025-09-03
    CVE published
    CVE List
  2. 2025-09-04
    Cloudflare ships a rule
    Sitecore - Remote Code Execution - CVE:CVE-2025-53691
  3. 2025-12-03
    F5 ships a rule
    Sitecore Unsafe Deserialization (2)

Social

2026-10-21: 0 posts2026-10-22: 0 posts2026-10-23: 0 posts2026-10-24: 0 posts2026-10-25: 0 posts2026-10-26: 0 posts2026-10-27: 0 posts2026-10-28: 0 posts2026-10-29: 0 posts2026-10-30: 0 posts2026-10-31: 0 posts2026-11-01: 0 posts2026-11-02: 0 posts2026-11-03: 0 posts

No posts seen yet on X, Bluesky, Mastodon, Hacker News or GitHub.

Vendor statements

Quoted
CloudflareWAF Managed Rules1 quoteBlocks by default

First rule 2025-09-04, 1 day after the CVE was published.

2025-09-04New rule…0ee2c15eDefault: BlockSource
Sitecore - Remote Code Execution - CVE:CVE-2025-53691. Previous action: N/A. New action: Block. This is a new detection
AWSAWS WAF Managed RulesNo public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. AWS often describes a vulnerability without naming its CVE (for example "Log4j"). We count only entries that name the CVE, so AWS coverage is understated.

Microsoft AzureFront Door and Application Gateway WAF (DRS)No public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. The rule tables name CVEs but carry no dates, so Azure is left out of every time-to-rule figure.

Google CloudCloud Armor preconfigured WAF rulesNo public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. Google names few CVEs: the release notes start in May 2024 and the rules reference lists CVEs without dates. Its cve-canary rules are opt-in.

FastlyNext-Gen WAF virtual patchesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

F5Attack signatures (Distributed Cloud WAF)1 quoteRule published

First rule 2025-12-03, 91 days after the CVE was published.

2025-12-03New rule200204029Source
Added: signature 200204029 "Sitecore Unsafe Deserialization (2)" (Server Side Code Injection, risk High), systems: Microsoft Windows, IIS, ASP, ASP.NET. References: CVE-2025-53691.
AkamaiApp & API Protector (Adaptive Security Engine)No public source

This vendor publishes no machine-readable rule changelog we can check.

OWASP CRSCore Rule Set (open source, used inside many WAFs)No public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. CRS rarely names CVEs: it relies on generic detections. Our own lab measures what it actually blocks.