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certfr-2025-avi-1051 — De multiples vulnérabilités ont été découvertes dans les produits IBM. Certaines d'entre elles permettent à un attaquan…

certfr-2025-avi-1051

EUVD-2026-260313

fkie_cve-2025-58369

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.

GHSA-rrw2-px9j-qffj — FS2 half-shutdown of socket during TLS handshake may result in spin loop on opposite side

Affected: Maven: co.fs2:fs2-io_2.12, Maven: co.fs2:fs2-io_2.13, Maven: co.fs2:fs2-io_3, Maven: co.fs2:fs2-io_0.26, Maven: co.fs2:fs2-io_0.27, Maven: co.fs2:fs2-io_2.11, Maven: co.fs2:fs2-io_2.12.0-M4, Maven: co.fs2:fs2-io_2.12.0-RC1, Maven: co.fs2:fs2-io_2.12.0-M5, Maven: co.fs2:fs2-io_2.12.0-RC2 and 1 more

### Impact When establishing a TLS session using `fs2-io` on the JVM using the `fs2.io.net.tls` package, 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. This CPU is consumed until the overall connection is closed.

This could be used as a denial of service attack on an fs2-io powered server -- for example, by opening many connections and putting them in a half-shutdown state.

Note: this issue impacts ember backed http4s servers with HTTPS as a result of ember using fs2's TLS support.

### Patches Fixed in fs2 3.12.2 and 3.13.0-M7.

### Workarounds No workarounds.

### For more information

If you have any questions or comments about this advisory:

[Open an issue.](https://github.com/typelevel/fs2/issues/new/choose) Contact the [Typelevel Security Team](https://github.com/typelevel/.github/blob/main/SECURITY.md).