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CVE-2021-42237· NVD / CVE Program· CNA mitre

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achi

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

CriticalCVSS 9.8 · v3.1KEVWeaponized No fix recorded
Published
Nov 5, 2021
Updated
Jul 9, 2026
EPSS
97.6% · 100th percentile
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Report tools

JSON

Action score

98

Now

Patch today or shut off access.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
29 / 30 · 97.6%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Mar 25, 2022. That signals real attacks, not theory.

Remediation deadline for government agencies: Apr 15, 2022.

Known to be used in ransomware campaigns.

Affected systems

VendorProduct
sitecoreexperience platform

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • sitecore experience platform7.5
  • sitecore experience platform8.0
  • sitecore experience platform8.1
  • sitecore experience platform8.2

Same product

sitecore: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-27068Deserialization of Untrusted Data in Sitecore Experience Platform through 10.2 allows remote attackers to run arbitrary code via ValidationR
    40Plan
  • CVE-2019-11080Sitecore Experience Platform (XP) prior to 9.1.1 is vulnerable to remote code execution via deserialization, aka TFS # 293863.
    39Monitor
  • CVE-2023-33653Sitecore Experience Platform (XP) v9.3 was discovered to contain an authenticated remote code execution (RCE) vulnerability via the componen
    36Monitor
  • CVE-2023-33652Sitecore Experience Platform (XP) v9.3 was discovered to contain an authenticated remote code execution (RCE) vulnerability via the componen
    36Monitor
  • CVE-2023-27067Directory Traversal vulnerability in Sitecore Experience Platform through 10.2 allows remote attackers to download arbitrary files via craft
    30Monitor
  • CVE-2023-27066Directory Traversal vulnerability in Site Core Experience Platform 10.2 and earlier allows authenticated remote attackers to download arbitr
    26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Metasploit moduleexploit/windows/http/sitecore_xp_cve_2021_42237Sitecore Experience Platform (XP) PreAuth Deserialization RCEexploit2021-11-02
Nuclei detection templateNuclei template CVE-2021-42237 —
Proof-of-concept repository on GitHubstars:142022-01-16
Proof-of-concept repository on GitHubstars:12022-06-30
Proof-of-concept repository on GitHubstars:02022-09-22

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-3 d
  2. Published
  3. First PoC+72 d
  4. CISA KEV+140 d
  5. TodaySep 29, 2026+1790 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-502 · Deserialization of Untrusted Data

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.

The bug in code

The whole CWE-502 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

python
payload = sock.recv(65536)job = pickle.loads(payload)

Fixed

python
payload = sock.recv(65536)if not hmac.compare_digest(sign(payload), header_sig):    raise PermissionError("invalid signature")job = JobSchema.validate(json.loads(payload))

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records