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Fencer Vulns
medium 5.3

CVE-2025-58369 json

fs2: Half-shutdown of socket during TLS handshake may result in spin loop on opposite side

published 2025-09-05 14 mo ago modified 2026-10-01 38 d ago also EUVD-2025-27048 , GHSA-rrw2-px9j-qffj

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven co.fs2:fs2-io_2.12 2.5.13, 3.12.2, 3.13.0-M7
  • maven co.fs2:fs2-io_2.13 2.5.13, 3.12.2, 3.13.0-M7
  • maven co.fs2:fs2-io_3 2.5.13, 3.12.2, 3.13.0-M7
  • co.fs2 fs2-io_0.26 2.5.13
  • typelevel fs2 2.5.13, 3.12.2, 3.13.0-M7
  • co.fs2 fs2-io_0.27 2.5.13
  • co.fs2 fs2-io_2.11 2.5.13
  • co.fs2 fs2-io_2.12 2.5.13, 3.12.2, 3.13.0-M7
  • co.fs2 fs2-io_2.12.0-m4 2.5.13
  • co.fs2 fs2-io_2.12.0-m5 2.5.13
  • co.fs2 fs2-io_2.12.0-rc1 2.5.13
  • co.fs2 fs2-io_2.12.0-rc2 2.5.13
  • co.fs2 fs2-io_2.13 2.5.13, 3.12.2, 3.13.0-M7
  • co.fs2 fs2-io_2.13.0-m5 2.5.13
  • co.fs2 fs2-io_3 2.5.13, 3.12.2, 3.13.0-M7

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
14 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
maven co.fs2:fs2-io_2.12
>=3.0.0-M1, <3.12.2
>=3.13.0-M1, <3.13.0-M7
<2.5.13
3.12.2
3.13.0-M7
2.5.13
maven co.fs2:fs2-io_2.13
>=3.0.0-M1, <3.12.2
>=3.13.0-M1, <3.13.0-M7
<2.5.13
3.12.2
3.13.0-M7
2.5.13
maven co.fs2:fs2-io_3
>=3.0.0-M1, <3.12.2
>=3.13.0-M1, <3.13.0-M7
<2.5.13
3.12.2
3.13.0-M7
2.5.13
maven co.fs2:fs2-io_0.26
all versions
 no fix listed
maven co.fs2:fs2-io_0.27
all versions
 no fix listed
maven co.fs2:fs2-io_2.11
all versions
 no fix listed
maven co.fs2:fs2-io_2.12.0-M4
all versions
 no fix listed
maven co.fs2:fs2-io_2.12.0-RC1
all versions
 no fix listed
maven co.fs2:fs2-io_2.12.0-M5
all versions
 no fix listed
maven co.fs2:fs2-io_2.12.0-RC2
all versions
 no fix listed
maven co.fs2:fs2-io_2.13.0-M5
all versions
 no fix listed

Affected products

  • typelevel fs2

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.