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CVE-2023-53933· NVD / CVE Program· CNA VulnCheck

Serendipity 2.4.0 Authenticated Remote Code Execution via File Upload

Serendipity 2.4.0 contains a remote code execution vulnerability that allows authenticated attackers to upload malicious PHP files with .phar extension. Attackers can upload files with system command payloads to the media upload endpoint and execute arbitrary commands on the server.

HighCVSS 8.7 · v4.0—No exploit No fix recorded
Published
Dec 17, 2025
Updated
Jun 17, 2026
EPSS
1.0% · 62th percentile
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Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.0%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
8.7
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

VendorProduct
s9yserendipity

Affected versions

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

  • s9y serendipity2.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • s9y Serendipity

    • 2.4.0affected

Same product

s9y: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-10964Serendipity before 2.3.4 on Windows allows remote attackers to execute arbitrary code because the filename of a renamed file may end with a
    40Plan
  • CVE-2011-1134Cross-Site Scripting (XSS) in Xinha, as included in the Serendipity package before 1.5.5, allows remote attackers to execute arbitrary code
    40Plan
  • CVE-2016-10752serendipity_moveMediaDirectory in Serendipity 2.0.3 allows remote attackers to upload and execute arbitrary PHP code because it mishandles a
    40Plan
  • CVE-2016-10082include/functions_installer.inc.php in Serendipity through 2.0.5 is vulnerable to File Inclusion and a possible Code Execution attack during
    40Plan
  • CVE-2005-1449Unknown vulnerability in serendipity_config_local.inc.php for Serendipity before 0.8 has unknown impact.
    40Plan
  • CVE-2005-1452Serendipity before 0.8 allows Chief users to "hide plugins installed by other users."
    40Plan

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

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

No dated events beyond publication.

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.

Variant candidates

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

  • CVE-2024-582827 days apartSerendipity 2.5.0 Remote Code Execution via Authenticated Media Upload
    34Monitor

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.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-434 · Unrestricted Upload of File with Dangerous Type

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

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

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