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Fencer Vulns
medium 6.5

CVE-2026-3784 json

wrong proxy connection reuse with credentials

published 2026-03-11 7 mo ago modified 2026-09-15 55 d ago also EUVD-2026-11139 , GHSA-5q3w-6p3j-mw6p , JLSEC-2026-438

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

Patch / fix

  • julia CURL_jll 8.20.0+0
  • julia LibCURL_jll 8.18.0+0
  • curl curl 8.14.2, 8.16.1, 8.19.0
  • Siemens RUGGEDCOM RST2428P V4.0
  • curl Debian 12 7.88.1-10+deb12u15
  • curl Debian 13 8.14.1-2+deb13u4
  • curl Debian 14 8.19.0-1

debian advisories DEBIAN-CVE-2026-3784

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.23
  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.8
  • curl Ubuntu 25.10 8.14.1-2ubuntu1.2
  • curl Ubuntu 26.10, Ubuntu 26.04 LTS 8.18.0-1ubuntu2
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm8
  • curl Ubuntu Pro 20.04 LTS 7.68.0-1ubuntu2.25+esm3

ubuntu advisories UBUNTU-CVE-2026-3784

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl hummingbird 1 8.19.0-3.1.hum1
  • libcurl hummingbird 1 8.19.0-3.1.hum1
  • libcurl-minimal hummingbird 1 8.19.0-3.1.hum1
  • curl hummingbird 1 8.22.0-1.1.hum1
  • libcurl hummingbird 1 8.22.0-1.1.hum1
  • libcurl-minimal hummingbird 1 8.22.0-1.1.hum1
  • curl RHEL 10.2 8.12.1-4.el10_2.3
  • libcurl RHEL 10.2 8.12.1-4.el10_2.3

red hat advisories RHSA-2026:7432RHSA-2026:77255RHSA-2026:72506RHSA-2026:55450RHSA-2026:6893

  • curl SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 8.14.1-160000.5.1
  • curl-mini SLES for SAP applications 16.0, SLES 16.0 8.14.1-160000.5.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.80.1
  • curl SLE Module for Basesystem 15 SP7 8.14.1-150700.7.14.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS, openSUSE Leap 15.6 8.14.1-150600.4.40.1
  • curl SLE Micro 5.2 8.14.1-150200.4.103.1
  • curl Linux Micro 6.1 8.14.1-slfo.1.1_6.1
  • curl Linux Micro 6.0 8.14.1-5.1

suse advisories SUSE-SU-2026:20760-1SUSE-SU-2026:20918-1SUSE-SU-2026:0921-1SUSE-SU-2026:0911-1SUSE-SU-2026:0903-1SUSE-SU-2026:0885-1

  • curl openSUSE Leap 16.0 8.14.1-160000.5.1
  • curl openSUSE Tumbleweed 8.19.0-1.1

opensuse advisories openSUSE-SU-2026:20404-1openSUSE-SU-2026:10371-1

  • curl Alpine 3.21 8.14.1-r3
  • curl Alpine 3.22 8.14.1-r4
  • curl Alpine 3.24, Alpine 3.23 8.19.0-r0

alpine advisories ALPINE-CVE-2026-3784

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 Azure Linux 3.0 8.11.1-6

azure linux advisories AZL-79679

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-3784 updated cvss 6.5

curl: curl: Unauthorized access due to improper HTTP proxy connection reuse

  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-rhel9-operator, openshift-sandboxed-containers/osc-operator-bundle, openshift-sandboxed-containers/osc-podvm-builder-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9, confidential-compute-attestation-tech-preview/trustee-rhel9 Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/vector-rhel9, openshift-logging/fluentd-rhel9, openshift-logging/eventrouter-rhel9, openshift-logging/logging-view-plugin-rhel9, openshift-logging/cluster-logging-rhel9-operator, openshift-logging/log-file-metric-exporter-rhel9, +1 more Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl Red Hat Enterprise Linux 8 curl, libcurl, libcurl-minimal
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 curl, libcurl, snphost, curl-minimal, libcurl-minimal Red Hat Enterprise Linux 10 snphost
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rust Red Hat OpenShift Container Platform 4 openshift4/recert-rhel9, openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat Enterprise Linux AppStream (v. 10) libcurl-devel 8.12.1-4.el10_2.3, curl-debuginfo 8.12.1-4.el10_2.3, curl-debugsource 8.12.1-4.el10_2.3, libcurl-debuginfo 8.12.1-4.el10_2.3, libcurl-minimal-debuginfo 8.12.1-4.el10_2.3
    fixed: vendor fix RHSA-2026:55450
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) libcurl-devel 8.12.1-1.el10_0.10, curl-debuginfo 8.12.1-1.el10_0.10, curl-debugsource 8.12.1-1.el10_0.10, libcurl-debuginfo 8.12.1-1.el10_0.10, libcurl-minimal-debuginfo 8.12.1-1.el10_0.10
    fixed: vendor fix RHSA-2026:72506
  • Red Hat Enterprise Linux BaseOS (v. 10) curl 8.12.1-4.el10_2.3, libcurl 8.12.1-4.el10_2.3, libcurl-minimal 8.12.1-4.el10_2.3
    fixed: vendor fix RHSA-2026:55450
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) curl 8.12.1-1.el10_0.10, libcurl 8.12.1-1.el10_0.10, libcurl-minimal 8.12.1-1.el10_0.10
    fixed: vendor fix RHSA-2026:72506
show 4 more
  • Red Hat Hardened Images curl 8.19.0-3.hum1, curl 8.19.0-3.1.hum1, curl 8.22.0-1.1.hum1, libcurl 8.19.0-3.hum1, libcurl 8.19.0-3.1.hum1, libcurl 8.22.0-1.1.hum1, +3 more
    fixed: vendor fix RHSA-2026:7432
  • Red Hat JBoss Core Services 2.4.62.SP5
    fixed: vendor fix RHSA-2026:56869
  • Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, rust-gdb, rust-src, +9 more Red Hat Enterprise Linux 10 rust, trustee, s390utils, trustee-guest-components
    not affected: component not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more
    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
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3584903 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
julia CURL_jll
<8.20.0+0
8.20.0+0
julia LibCURL_jll
<8.18.0+0
8.18.0+0

Affected products

  • curl curl
  • Siemens RUGGEDCOM RST2428P

Classification

Weakness
  • CWE-305 Authentication Bypass by Primary Weakness

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.