Description
fs2 is a compositional, streaming I/O library for Scala. Versions up to and including 2.5.12, 3.0.0-M1 through 3.12.2, and 3.13.0-M1 through 3.13.0-M6 are 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 2.5.13, 3.12.1, and 3.13.0-M7.
Published: 2025-09-05
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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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
History

Fri, 07 Nov 2025 12:00:00 +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. fs2 is a compositional, streaming I/O library for Scala. Versions up to and including 2.5.12, 3.0.0-M1 through 3.12.2, and 3.13.0-M1 through 3.13.0-M6 are 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 2.5.13, 3.12.1, and 3.13.0-M7.
References

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'}

Subscriptions

Typelevel Fs2
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-11-07T11:52:43.148Z

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: 2025-11-07T12:15:34.797

Link: CVE-2025-58369

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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

Weaknesses