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.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-27048 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.
Github GHSA Github GHSA GHSA-rrw2-px9j-qffj FS2 half-shutdown of socket during TLS handshake may result in spin loop on opposite side
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

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

Type Values Removed Values Added
First Time appeared Typelevel
Typelevel fs2
Vendors & Products Typelevel
Typelevel fs2

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

Type Values Removed Values Added
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:

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.

cve-icon OpenCVE Enrichment

Updated: 2025-09-07T15:24:59Z