How severe is CVE-2026-59725?

CVE-2026-59725 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-59725 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59725?

CVE-2026-59725 affects Socket Engine.io. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-59725?

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.

When was CVE-2026-59725 published?

CVE-2026-59725 was published on 2026-07-08 and last updated on 2026-07-13.

CVE-2026-59725

CVE-2026-59725 is a high-severity vulnerability in Socket Engine.io with a CVSS 3.x base score of 7.5. 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-404.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-404
Affected product: Socket Engine.io
Published: 2026-07-08
Last modified: 2026-07-13

Description

Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.

Frequently asked questions

What is CVE-2026-59725?: Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.
How severe is CVE-2026-59725?: CVE-2026-59725 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-59725 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59725?: CVE-2026-59725 affects Socket Engine.io. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-59725?: 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.
When was CVE-2026-59725 published?: CVE-2026-59725 was published on 2026-07-08 and last updated on 2026-07-13.

References

Affected products (1)

cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*

More vulnerabilities in Socket Engine.io

CVE-2026-59724 — High (CVSS 7.5): Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO…
CVE-2022-21676 — High (CVSS 7.5): Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for…
CVE-2020-36048 — High (CVSS 7.5): Engine.IO before 4.0.0 allows attackers to cause a denial of service (resource consumption) via a POST request to the…
CVE-2022-41940 — High (CVSS 7.1): Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for…
CVE-2023-31125 — Medium (CVSS 6.5): Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for…

All CVEs affecting Socket Engine.io →

Other CWE-404 vulnerabilities

CVE-2023-24444 — Critical (CVSS 9.8): Jenkins OpenID Plugin 2.4 and earlier does not invalidate the previous session on login.
CVE-2024-31611 — Critical (CVSS 9.1): SeaCMS 12.9 has a file deletion vulnerability via admin_template.php.
CVE-2018-8450 — High (CVSS 8.8): A remote code execution vulnerability exists when Windows Search handles objects in memory, aka "Windows Search Remote…
CVE-2026-11317 — High (CVSS 8.7): A denial of service security issue exists in the affected product. The security issue stems from a fault occurring when…
CVE-2022-25762 — High (CVSS 8.6): If a web application sends a WebSocket message concurrently with the WebSocket connection closing when running on…
CVE-2020-26070 — High (CVSS 8.6): A vulnerability in the ingress packet processing function of Cisco IOS XR Software for Cisco ASR 9000 Series…

Browse all CWE-404 vulnerabilities →