Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M

CVE-2026-33645Fireshare has Path Traversal Arbitrary File Write in `/api/uploadChunked`

High 7.1

In plain English

A high-severity path traversal in fireshare from ShaneIsrael. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.4%top 61.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
ShaneIsrael	fireshare	= 1.5.2

Weakness: CWE-22, CWE-73 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

References

https://github.com/ShaneIsrael/fireshare/security/advisories/GHSA-7q8r-vpq3-89m7 x_refsource_CONFIRM
https://github.com/ShaneIsrael/fireshare/releases/tag/v1.5.2 x_refsource_MISC