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Fencer Vulns
high 7.5

CVE-2025-5399 json

WebSocket endless loop

published 2025-06-07 17 mo ago modified 2026-07-18 3 mo ago also EUVD-2025-17371 , GHSA-8h93-38hx-vv92 , JLSEC-2026-434

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted packet which makes libcurl get trapped in an endless busy-loop.

There is no other way for the application to escape or exit this loop other than killing the thread/process.

This might be used to DoS libcurl-using application.

Patch / fix

  • julia CURL_jll 8.14.1+0
  • julia LibCURL_jll 8.14.1+0
  • haxx curl 8.14.1
  • curl Debian 14, Debian 13 8.14.1-1

debian advisories DEBIAN-CVE-2025-5399

  • curl SLE Module for Basesystem 15 SP7, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 8.14.1-150600.4.28.1
  • curl Linux Micro 6.1 8.14.1-slfo.1.1_1.1

suse advisories SUSE-SU-2025:03198-1SUSE-SU-2025:20675-1

  • curl openSUSE Tumbleweed 8.14.1-4.1

opensuse advisories openSUSE-SU-2025:15213-1

  • mecab AlmaLinux 9 0.996-3.module_el9.6.0+152+8cbce00c.4
  • mysql AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5
  • mysql-libs AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5
  • mysql-test AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5
  • mecab-ipadic AlmaLinux 9 2.7.0.20070801-24.module_el9.6.0+152+8cbce00c
  • mysql-common AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5
  • mysql-errmsg AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5
  • mysql-server AlmaLinux 9 8.4.6-1.module_el9.6.0+180+a4e757e5

almalinux advisories ALSA-2025:16046ALSA-2025:15699

  • mysql8.4 Rocky Linux 10 8.4.6-2.el10_0
  • mysql-selinux Rocky Linux 10 1.0.14-1.el10_0

rocky linux advisories RLSA-2025:15699

  • curl Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 8.14.1-r0

alpine advisories ALPINE-CVE-2025-5399

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl Arch Linux 8.14.1-1

arch linux advisories AVG-2895

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-5399 updated cvss 4.3

curl: libcurl: WebSocket endless loop

  • Red Hat Confidential Compute Attestation confidential-compute-attestation-tech-preview/trustee-rhel9 Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal Red Hat Enterprise Linux 9 curl, rust, cargo, clippy, libcurl, rustfmt, +14 more Red Hat Enterprise Linux 10 curl, rust, snphost, trustee-guest-components
    +3 more products
    Red Hat JBoss Core Services curl Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

1.44% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3168039 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia CURL_jll
>=8.13.0+0, <8.14.1+0
8.14.1+0
julia LibCURL_jll
>=8.13.0+0, <8.14.1+0
8.14.1+0

Affected products

  • curl curl

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

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.