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HIGH

CVE-2026-59725

CVSS v3

7.5

HIGH

EPSS Score

0.6 %

exploit probability, as of 2026-10-17

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • engine.ionpmfrom 4.1.0 · fixed in 6.6.7

Vendor advisories

  • CVE-2026-59725 Red Hat Product Security34 products fixed · 4 known affected

    socket.io: engine.io: Socket.IO: Denial of Service via invalid binary POST requests

    rhelai3/bootc-cuda-rhel9 as a component of Red Hat Enterprise Linux AI (RHEL AI) 3 · rhelai3/bootc-gaudi-rhel9 as a component of Red Hat Enterprise Linux AI (RHEL AI) 3 · rhelai3/bootc-rocm-rhel9 as a component of Red Hat Enterprise Linux AI (RHEL AI) 3

  • RHSA-2026:42986 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

  • RHSA-2026:37577 Red Hat Product Security25 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-07-08
Last Modified
2026-07-08
GitHub Advisory
GHSA-r635-g3xr-vw7x

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.

Is CVE-2026-59725 actively exploited?

Active exploitation of CVE-2026-59725 has not been confirmed. Its EPSS score was 0.6% on 2026-10-17, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-59725?

CVE-2026-59725 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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