fs2 is a compositional, streaming I/O library for Scala. Versions 3.12.2 and lower and 3.13.0-M1 through 3.13.0-M6 is vulnerable to denial of service attacks though TLS sessions using fs2-io on the JVM using the fs2.io.net.tls package. When establishing a TLS session, if one side of the connection shuts down `write` while the peer side is awaiting more data to progress the TLS handshake, the peer side will spin loop on the socket read, fully utilizing a CPU. The CPU is consumed until the overall connection is closed, potentially shutting down a fs2-io powered server. This issue is fixed in versions 3.12.1 and 3.13.0-M7.
History

Mon, 08 Sep 2025 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 07 Sep 2025 15:30:00 +0000

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First Time appeared Typelevel
Typelevel fs2
Vendors & Products Typelevel
Typelevel fs2

Fri, 05 Sep 2025 22:15:00 +0000

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Description fs2 is a compositional, streaming I/O library for Scala. Versions 3.12.2 and lower and 3.13.0-M1 through 3.13.0-M6 is vulnerable to denial of service attacks though TLS sessions using fs2-io on the JVM using the fs2.io.net.tls package. When establishing a TLS session, if one side of the connection shuts down `write` while the peer side is awaiting more data to progress the TLS handshake, the peer side will spin loop on the socket read, fully utilizing a CPU. The CPU is consumed until the overall connection is closed, potentially shutting down a fs2-io powered server. This issue is fixed in versions 3.12.1 and 3.13.0-M7.
Title fs2: Half-shutdown of socket during TLS handshake may result in spin loop on opposite side
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2025-09-05T21:59:58.981Z

Updated: 2025-09-08T20:09:32.825Z

Reserved: 2025-08-29T16:19:59.012Z

Link: CVE-2025-58369

cve-icon Vulnrichment

Updated: 2025-09-08T20:09:29.795Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-05T22:15:34.883

Modified: 2025-09-08T16:25:38.810

Link: CVE-2025-58369

cve-icon Redhat

No data.