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8.1
HIGH CVSS 3.1
CVE-2026-33645
Fireshare has Path Traversal Arbitrary File Write in `/api/uploadChunked`
Overview
Description

Fireshare facilitates self-hosted media and link sharing. In version 1.5.1, an authenticated path traversal vulnerability in Fireshare’s chunked upload endpoint allows an attacker to write arbitrary files outside the intended upload directory. The `checkSum` multipart field is used directly in filesystem path construction without sanitization or containment checks. This enables unauthorized file writes to attacker-chosen paths writable by the Fireshare process (e.g., container `/tmp`), violating integrity and potentially enabling follow-on attacks depending on deployment. Version 1.5.2 fixes the issue.

Details
INFO

Published Date :

March 26, 2026, 9:17 p.m.

Last Modified :

March 30, 2026, 6:12 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-33645 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Shaneisrael fireshare
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH [email protected]
CVSS 3.1 HIGH [email protected]
Solution
Update Fireshare to version 1.5.2 to fix the path traversal vulnerability.
  • Update Fireshare to version 1.5.2.
  • Verify file write protections are in place.
Public PoC/Exploit Available at Github

CVE-2026-33645 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-33645.

URL Resource
https://github.com/ShaneIsrael/fireshare/releases/tag/v1.5.2 Release Notes
https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7 Vendor Advisory
https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7 Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-33645 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-33645 weaknesses.

CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-126: Path Traversal Path Traversal CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
QiaoNPC/QiaoNPC

None

Python

Updated: 5 days, 18 hours ago
0 stars 0 fork 0 watcher
Born at : Dec. 17, 2025, 7:32 a.m. This repo has been linked 10 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-33645 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-33645 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Mar. 30, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
    Added CWE CWE-22
    Added CPE Configuration OR *cpe:2.3:a:shaneisrael:fireshare:1.5.1:*:*:*:*:*:*:*
    Added Reference Type GitHub, Inc.: https://github.com/ShaneIsrael/fireshare/releases/tag/v1.5.2 Types: Release Notes
    Added Reference Type CISA-ADP: https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7 Types: Vendor Advisory
    Added Reference Type GitHub, Inc.: https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7 Types: Vendor Advisory
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Mar. 27, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7
  • New CVE Received by [email protected]

    Mar. 26, 2026

    Action Type Old Value New Value
    Added Description Fireshare facilitates self-hosted media and link sharing. In version 1.5.1, an authenticated path traversal vulnerability in Fireshare’s chunked upload endpoint allows an attacker to write arbitrary files outside the intended upload directory. The `checkSum` multipart field is used directly in filesystem path construction without sanitization or containment checks. This enables unauthorized file writes to attacker-chosen paths writable by the Fireshare process (e.g., container `/tmp`), violating integrity and potentially enabling follow-on attacks depending on deployment. Version 1.5.2 fixes the issue.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
    Added CWE CWE-22
    Added CWE CWE-73
    Added Reference https://github.com/ShaneIsrael/fireshare/releases/tag/v1.5.2
    Added Reference https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 8.1
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact