CVE-2025-40710

CVE-2025-40710 is a low-severity vulnerability with a CVSS 4.0 base score of 2.3. 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-74.

Key facts

Description

Host Header Injection (HHI) vulnerability in the Hotspot Shield VPN client, which can induce unexpected behaviour when accessing third-party web applications through the VPN tunnel. Although such applications do not present this vulnerability per se, the use of the tunnel, together with a forged Host header, can cause the VPN client to redirect or forward HTTP requests to servers other than those originally intended, leading to consequences such as open redirects or delivery of traffic to infrastructure controlled by an attacker. This does not imply a flaw in the target applications, but in how the VPN client internally handles outgoing headers and requests.

Frequently asked questions

What is CVE-2025-40710?
Host Header Injection (HHI) vulnerability in the Hotspot Shield VPN client, which can induce unexpected behaviour when accessing third-party web applications through the VPN tunnel. Although such applications do not present this vulnerability per se, the use of the tunnel, together with a forged Host header, can cause the VPN client to redirect or forward HTTP requests to servers other than those originally intended, leading to consequences such as open redirects or delivery of traffic to infrastructure controlled by an attacker. This does not imply a flaw in the target applications, but in how the VPN client internally handles outgoing headers and requests.
How severe is CVE-2025-40710?
CVE-2025-40710 has a CVSS 4.0 base score of 2.3, rated low severity.
Is CVE-2025-40710 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40710?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40710 have an EU (EUVD) identifier?
Yes. CVE-2025-40710 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19527.
When was CVE-2025-40710 published?
CVE-2025-40710 was published on 2025-06-30 and last updated on 2026-06-17.

References

Other CWE-74 (Improper Neutralization of Special Elements (Injection)) vulnerabilities

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