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Fencer Vulns
high 8.1

CVE-2026-8286 json

wrong STARTTLS connection reuse

published 2026-07-03 4 mo ago modified 2026-09-15 55 d ago also EUVD-2026-41503 , GHSA-32xh-3x3c-6g6h , JLSEC-2026-1211

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

Patch / fix

  • julia CURL_jll 8.21.0+0
  • julia LibCURL_jll 8.21.0+0
  • curl curl 8.14.2, 8.16.1, 8.20.1
  • curl Debian 13 8.14.1-2+deb13u7
  • curl Debian 14 8.21.0~rc2-1

debian advisories DEBIAN-CVE-2026-8286

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.25
  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.10
  • curl Ubuntu 25.10 8.14.1-2ubuntu1.4
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.2
  • curl Ubuntu Pro 14.04 LTS 7.35.0-1ubuntu2.20+esm20
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm16
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm9
  • curl Ubuntu Pro 20.04 LTS 7.68.0-1ubuntu2.25+esm4

ubuntu advisories UBUNTU-CVE-2026-8286

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 RHEL 8 7.61.1-34.el8_10.13
  • libcurl RHEL 8 7.61.1-34.el8_10.13
  • libcurl-minimal RHEL 8 7.61.1-34.el8_10.13
  • curl RHEL 10.2 8.12.1-4.el10_2.3
  • libcurl RHEL 10.2 8.12.1-4.el10_2.3
  • libcurl-minimal RHEL 10.2 8.12.1-4.el10_2.3
  • curl RHEL 9 7.76.1-40.el9_8.5
  • libcurl RHEL 9 7.76.1-40.el9_8.5

red hat advisories RHSA-2026:72506RHSA-2026:57462RHSA-2026:55450RHSA-2026:55439RHSA-2026:29017RHSA-2026:34975

  • curl Linux Micro 6.1 8.14.1-slfo.1.1_8.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.86.1
  • curl Linux Micro 6.0 8.14.1-7.1
  • curl SLE Module for Basesystem 15 SP7 8.14.1-150700.7.20.1
  • curl SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 8.14.1-160000.8.1
  • curl-mini SLES for SAP applications 16.0, SLES 16.0 8.14.1-160000.8.1
  • curl SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 8.0.1-11.126.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.14.1-150600.4.46.1

suse advisories SUSE-SU-2026:3814-1SUSE-SU-2026:22889-1SUSE-SU-2026:3043-1SUSE-SU-2026:22709-1SUSE-SU-2026:2926-1SUSE-SU-2026:2925-1

  • curl openSUSE Tumbleweed 8.21.0-1.1
  • curl openSUSE Leap 16.0 8.14.1-160000.8.1

opensuse advisories openSUSE-SU-2026:11230-1openSUSE-SU-2026:21272-1

  • curl AlmaLinux 8 7.61.1-34.el8_10.13
  • libcurl AlmaLinux 8 7.61.1-34.el8_10.13
  • libcurl-minimal AlmaLinux 8 7.61.1-34.el8_10.13
  • curl AlmaLinux 9 7.76.1-40.el9_8.5
  • libcurl AlmaLinux 9 7.76.1-40.el9_8.5
  • curl-minimal AlmaLinux 9 7.76.1-40.el9_8.5
  • libcurl-minimal AlmaLinux 9 7.76.1-40.el9_8.5

almalinux advisories ALSA-2026:57462ALSA-2026:55439

  • curl Rocky Linux 8 7.61.1-34.el8_10.13
  • curl Rocky Linux 9 7.76.1-40.el9_8.5

rocky linux advisories RLSA-2026:57462RLSA-2026:55439

  • curl Alpine 3.21 8.14.1-r3
  • curl Alpine 3.22 8.14.1-r4
  • curl Alpine 3.23 8.22.0-r0
  • curl Alpine 3.24 8.21.0-r0

alpine advisories ALPINE-CVE-2026-8286

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 8.11.1-10
  • cmake Azure Linux 3.0 3.30.3-15

azure linux advisories AZL-91815AZL-91842

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-2026-8286 updated cvss 8.1

curl: curl: Insecure connection establishment due to TLS configuration mismatch

  • Red Hat Enterprise Linux 6 curl, libcurl
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 curl, libcurl Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 cert-manager/cert-manager-operator-rhel9 1791788287, cert-manager/jetstack-cert-manager-rhel9 1791371069, cert-manager/cert-manager-istio-csr-rhel9 1791378395, cert-manager/cert-manager-operator-bundle 1791970484, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791371080
    fixed: vendor fix RHSA-2026:82336
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.19 cert-manager/cert-manager-operator-rhel9 1788348522, cert-manager/jetstack-cert-manager-rhel9 1788348571, cert-manager/cert-manager-istio-csr-rhel9 1788348594, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1788348571
    fixed: vendor fix RHSA-2026:63140
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-operator-rhel9 1790272426, cert-manager/cert-manager-operator-rhel9 1790589855, cert-manager/jetstack-cert-manager-rhel9 1790223279, cert-manager/jetstack-cert-manager-rhel9 1790589912, cert-manager/cert-manager-istio-csr-rhel9 1790223719, cert-manager/cert-manager-istio-csr-rhel9 1790589914, +2 more
    fixed: vendor fix RHSA-2026:72475
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1788206196, discovery/discovery-server-rhel9 1788205779
    fixed: vendor fix RHSA-2026:61783
  • Red Hat Enterprise Linux AppStream (v. 9) libcurl-devel 7.76.1-40.el9_8.5, curl-debuginfo 7.76.1-40.el9_8.5, curl-debugsource 7.76.1-40.el9_8.5, libcurl-debuginfo 7.76.1-40.el9_8.5, curl-minimal-debuginfo 7.76.1-40.el9_8.5, libcurl-minimal-debuginfo 7.76.1-40.el9_8.5
    fixed: vendor fix RHSA-2026:55439
show 14 more
  • 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 AppStream EUS (v.9.6) libcurl-devel 7.76.1-31.el9_6.4, curl-debuginfo 7.76.1-31.el9_6.4, curl-debugsource 7.76.1-31.el9_6.4, libcurl-debuginfo 7.76.1-31.el9_6.4, curl-minimal-debuginfo 7.76.1-31.el9_6.4, libcurl-minimal-debuginfo 7.76.1-31.el9_6.4
    fixed: vendor fix RHSA-2026:93454
  • Red Hat Enterprise Linux BaseOS (v. 8) curl 7.61.1-34.el8_10.13, libcurl 7.61.1-34.el8_10.13, libcurl-minimal 7.61.1-34.el8_10.13
    fixed: vendor fix RHSA-2026:57462
  • Red Hat Enterprise Linux BaseOS (v. 9) curl 7.76.1-40.el9_8.5, libcurl 7.76.1-40.el9_8.5, curl-minimal 7.76.1-40.el9_8.5, libcurl-minimal 7.76.1-40.el9_8.5
    fixed: vendor fix RHSA-2026:55439
  • 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
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) curl 7.76.1-31.el9_6.4, libcurl 7.76.1-31.el9_6.4, curl-minimal 7.76.1-31.el9_6.4, libcurl-minimal 7.76.1-31.el9_6.4
    fixed: vendor fix RHSA-2026:93454
  • Red Hat Hardened Images rust 1.96.1-1.hum1, cargo 1.96.1-1.hum1, clippy 1.96.1-1.hum1, curl 8.21.0-0.1.hum1, rustfmt 1.96.1-1.hum1, rust-gdb 1.96.1-1.hum1, +14 more
    fixed: vendor fix RHSA-2026:34975
  • Red Hat JBoss Core Services 2.4.62.SP5
    fixed: vendor fix RHSA-2026:56869
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202608251819, rhcos 4.22.9.8.202609081748
    fixed: vendor fix RHSA-2026:60440
  • Red Hat OpenShift Dev Spaces 3.30 devspaces/code-rhel9 1787762793
    fixed: vendor fix RHSA-2026:62260
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1788880464, rhui5/rhua-rhel9 1788880581, rhui5/haproxy-rhel9 1788880456, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1788765051, rhui5/installer-tp-rhel9 1787135742, +2 more
    fixed: vendor fix RHSA-2026:66018
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/jetstack-cert-manager-acmesolver-rhel9 1790223630 Red Hat OpenShift AI (RHOAI) rhoai/odh-llama-stack-k8s-operator-rhel9 Red Hat OpenShift Dev Spaces 3.30 devspaces/udi-rhel9 1787764814, devspaces/server-rhel9 1787757597, devspaces/openvsx-rhel9 1787759145, devspaces/traefik-rhel9 1787756799, devspaces/udi-base-rhel9 1787761882, devspaces/code-sshd-rhel9 1787762385, +10 more Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9 Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206
    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
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3718195 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
julia CURL_jll
<8.21.0+0
8.21.0+0
julia LibCURL_jll
<8.21.0+0
8.21.0+0

Affected products

  • curl curl

Classification

Weakness
  • CWE-295 Improper Certificate Validation

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.