How severe is CVE-2025-71381?

CVE-2025-71381 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-71381 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-71381?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2025-71381 published?

CVE-2025-71381 was published on 2026-06-30 and last updated on 2026-07-02.

CVE-2025-71381

CVE-2025-71381 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. 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-113.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 6.9
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-113
Published: 2026-06-30
Last modified: 2026-07-02

Description

Hono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.

Frequently asked questions

What is CVE-2025-71381?: Hono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.
How severe is CVE-2025-71381?: CVE-2025-71381 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-71381 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-71381?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2025-71381 published?: CVE-2025-71381 was published on 2026-06-30 and last updated on 2026-07-02.

References

Other CWE-113 (HTTP Response Splitting) vulnerabilities

CVE-2026-38967 — Critical (CVSS 9.8): CrowCpp Crow through v1.3.1 HTTP is vulnerable to response header injection via unvalidated response header values.
CVE-2026-34520 — Critical (CVSS 9.1): AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, the C parser…
CVE-2025-53007 — High (CVSS 8.9): arduino-esp32 provides an Arduino core for the ESP32. Versions prior to 3.3.0-RC1 and 3.2.1 contain a HTTP Response…
CVE-2024-52875 — High (CVSS 8.8): An issue was discovered in GFI Kerio Control 9.2.5 through 9.4.5. The dest GET parameter passed to the…
CVE-2018-0689 — High (CVSS 8.8): HTTP header injection vulnerability in SEIKO EPSON printers and scanners (DS-570W firmware versions released prior to…
CVE-2018-11347 — High (CVSS 8.8): The YunoHost 2.7.2 through 2.7.14 web application is affected by one HTTP Response Header Injection. This flaw allows…

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