How severe is CVE-2026-33645?

CVE-2026-33645 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.

Is CVE-2026-33645 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33645?

CVE-2026-33645 affects Shaneisrael Fireshare. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33645?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-33645 have an EU (EUVD) identifier?

Yes. CVE-2026-33645 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16416.

When was CVE-2026-33645 published?

CVE-2026-33645 was published on 2026-03-26 and last updated on 2026-06-17.

CVE-2026-33645

CVE-2026-33645 is a high-severity vulnerability in Shaneisrael Fireshare with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-16416
Weakness: CWE-22
Affected product: Shaneisrael Fireshare
Published: 2026-03-26
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-33645?: 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.
How severe is CVE-2026-33645?: CVE-2026-33645 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.
Is CVE-2026-33645 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33645?: CVE-2026-33645 affects Shaneisrael Fireshare. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33645?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-33645 have an EU (EUVD) identifier?: Yes. CVE-2026-33645 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16416.
When was CVE-2026-33645 published?: CVE-2026-33645 was published on 2026-03-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:shaneisrael:fireshare:1.5.1:*:*:*:*:*:*:*

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