How severe is CVE-2023-53959?

CVE-2023-53959 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-53959 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-53959?

CVE-2023-53959 affects Filezilla-project Filezilla Client. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-53959?

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

Does CVE-2023-53959 have an EU (EUVD) identifier?

Yes. CVE-2023-53959 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-204606.

When was CVE-2023-53959 published?

CVE-2023-53959 was published on 2025-12-19 and last updated on 2026-06-17.

CVE-2023-53959

CVE-2023-53959 is a critical-severity vulnerability in Filezilla-project Filezilla Client with a CVSS 3.x base score of 9.8. 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-427.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 8.5
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-204606
Weakness: CWE-427
Affected product: Filezilla-project Filezilla Client
Published: 2025-12-19
Last modified: 2026-06-17

Description

FileZilla Client 3.63.1 contains a DLL hijacking vulnerability that allows attackers to execute malicious code by placing a crafted TextShaping.dll in the application directory. Attackers can generate a reverse shell payload using msfvenom and replace the missing DLL to achieve remote code execution when the application launches.

Frequently asked questions

What is CVE-2023-53959?: FileZilla Client 3.63.1 contains a DLL hijacking vulnerability that allows attackers to execute malicious code by placing a crafted TextShaping.dll in the application directory. Attackers can generate a reverse shell payload using msfvenom and replace the missing DLL to achieve remote code execution when the application launches.
How severe is CVE-2023-53959?: CVE-2023-53959 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-53959 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-53959?: CVE-2023-53959 affects Filezilla-project Filezilla Client. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-53959?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2023-53959 have an EU (EUVD) identifier?: Yes. CVE-2023-53959 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-204606.
When was CVE-2023-53959 published?: CVE-2023-53959 was published on 2025-12-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:filezilla-project:filezilla_client:3.63.1:*:*:*:*:*:*:*

More vulnerabilities in Filezilla-project Filezilla Client

CVE-2019-5429 — High (CVSS 7.8): Untrusted search path in FileZilla before 3.41.0-rc1 allows an attacker to gain privileges via a malicious 'fzsftp'…
CVE-2022-29620 — Medium (CVSS 6.5): FileZilla v3.59.0 allows attackers to obtain cleartext passwords of connected SSH or FTP servers via a memory dump.-…
CVE-2016-15003 — Medium (CVSS 6.3): A vulnerability has been found in FileZilla Client 3.17.0.0 and classified as problematic. This vulnerability affects…
CVE-2019-25683 — Medium (CVSS 6.2): FileZilla 3.40.0 contains a denial of service vulnerability in the local search functionality that allows local…
CVE-2024-31497 — Medium (CVSS 5.9): In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521…
CVE-2023-48795 — Medium (CVSS 5.9): The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows…

All CVEs affecting Filezilla-project Filezilla Client →

Other CWE-427 (Uncontrolled Search Path Element) vulnerabilities

CVE-2025-4981 — Critical (CVSS 9.9): Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to…
CVE-2025-69599 — Critical (CVSS 9.8): RayVentory Scan Engine through 12.6 Update 8 allows attackers to gain privileges if they control the value of the PATH…
CVE-2019-25268 — Critical (CVSS 9.8): NREL BEopt 2.8.0.0 contains a DLL hijacking vulnerability that allows attackers to load arbitrary libraries by tricking…
CVE-2025-65741 — Critical (CVSS 9.8): Sublime Text 3 Build 3208 or prior for MacOS is vulnerable to Dylib Injection. An attacker could compile a .dylib file…
CVE-2024-23054 — Critical (CVSS 9.8): An issue in Plone Docker Official Image 5.2.13 (5221) open-source software that could allow for remote code execution…
CVE-2023-31543 — Critical (CVSS 9.8): A dependency confusion in pipreqs v0.3.0 to v0.4.11 allows attackers to execute arbitrary code via uploading a crafted…

Browse all CWE-427 (Uncontrolled Search Path Element) vulnerabilities →