What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-26 · updated 2026-06-17
• Weakness: CWE-22

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

• ShaneIsrael fireshare: 1.5.1

References

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

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