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Fencer Vulns
critical 9.1

CVE-2026-8924 json

trailing dot domain super cookie

published 2026-07-03 4 mo ago modified 2026-09-15 55 d ago also EUVD-2026-41505 , GHSA-hm6c-rc5h-32m9 , JLSEC-2026-1213

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

Summary

A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits to unrelated third-party domains.

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-2026-8924

  • 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 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-2026-8924

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 9 7.76.1-40.el9_8.8
  • libcurl RHEL 9 7.76.1-40.el9_8.8
  • curl-minimal RHEL 9 7.76.1-40.el9_8.8
  • libcurl-minimal RHEL 9 7.76.1-40.el9_8.8
  • curl RHEL 10.2 8.12.1-4.el10_2.6
  • libcurl RHEL 10.2 8.12.1-4.el10_2.6
  • libcurl-minimal RHEL 10.2 8.12.1-4.el10_2.6
  • curl hummingbird 1 8.21.0-0.1.hum1

red hat advisories RHSA-2026:80511RHSA-2026:72506RHSA-2026:69125RHSA-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

  • libpsl openSUSE Tumbleweed 0.23.0-1.1
  • curl openSUSE Tumbleweed 8.21.0-1.1
  • curl openSUSE Leap 16.0 8.14.1-160000.8.1

opensuse advisories openSUSE-SU-2026:11266-1openSUSE-SU-2026:11230-1openSUSE-SU-2026:21272-1

  • curl AlmaLinux 8 7.61.1-34.el8_10.18
  • libcurl AlmaLinux 8 7.61.1-34.el8_10.18
  • libcurl-minimal AlmaLinux 8 7.61.1-34.el8_10.18
  • curl AlmaLinux 9 7.76.1-40.el9_8.8
  • libcurl AlmaLinux 9 7.76.1-40.el9_8.8
  • curl-minimal AlmaLinux 9 7.76.1-40.el9_8.8
  • libcurl-minimal AlmaLinux 9 7.76.1-40.el9_8.8
  • curl AlmaLinux 10 8.12.1-4.el10_2.6

almalinux advisories ALSA-2026:92368ALSA-2026:80511ALSA-2026:69125

  • curl Rocky Linux 8 7.61.1-34.el8_10.18
  • curl Rocky Linux 9 7.76.1-40.el9_8.8
  • curl Rocky Linux 10 8.12.1-4.el10_2.6

rocky linux advisories RLSA-2026:92368RLSA-2026:80511RLSA-2026:69125

  • 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-2026-8924

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

  • cmake Azure Linux 3.0 3.30.3-15

azure linux advisories AZL-91845

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-2026-8924 updated cvss 6.5

curl: curl: Cookie injection via malicious HTTP server using super cookies

  • Red Hat Enterprise Linux 6 curl, libcurl
    affected: workaround, no fix planned “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve”
  • Red Hat Enterprise Linux 7 curl, libcurl Red Hat JBoss Core Services jbcs-httpd24-curl, jbcs-httpd24-libcurl Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Satellite 6 puppet-agent
    affected: workaround, no fix available “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve”
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1791460851
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:79357
  • Red Hat Enterprise Linux AppStream (v. 9) libcurl-devel 7.76.1-40.el9_8.8, curl-debuginfo 7.76.1-40.el9_8.8, curl-debugsource 7.76.1-40.el9_8.8, libcurl-debuginfo 7.76.1-40.el9_8.8, curl-minimal-debuginfo 7.76.1-40.el9_8.8, libcurl-minimal-debuginfo 7.76.1-40.el9_8.8
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:80511
  • Red Hat Enterprise Linux AppStream (v. 10) libcurl-devel 8.12.1-4.el10_2.6, curl-debuginfo 8.12.1-4.el10_2.6, curl-debugsource 8.12.1-4.el10_2.6, libcurl-debuginfo 8.12.1-4.el10_2.6, libcurl-minimal-debuginfo 8.12.1-4.el10_2.6
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:69125
  • 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 “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” 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 “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:93454
  • Red Hat Enterprise Linux BaseOS (v. 8) curl 7.61.1-34.el8_10.18, libcurl 7.61.1-34.el8_10.18, libcurl-minimal 7.61.1-34.el8_10.18
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:92368
show 12 more
  • Red Hat Enterprise Linux BaseOS (v. 9) curl 7.76.1-40.el9_8.8, libcurl 7.76.1-40.el9_8.8, curl-minimal 7.76.1-40.el9_8.8, libcurl-minimal 7.76.1-40.el9_8.8
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:80511
  • Red Hat Enterprise Linux BaseOS (v. 10) curl 8.12.1-4.el10_2.6, libcurl 8.12.1-4.el10_2.6, libcurl-minimal 8.12.1-4.el10_2.6
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:69125
  • 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 “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” 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 “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” 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 “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:34975
  • Red Hat JBoss Core Services 2.4.62.SP5
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:56869
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202610241758
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:89197
  • Red Hat Satellite 6.16 for RHEL 8 openvox-agent 8.31.1-1.el8sat Red Hat Satellite 6.16 for RHEL 9 openvox-agent 8.31.1-1.el9sat
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:92858
  • Red Hat Satellite 6.17 for RHEL 9 openvox-agent 8.31.1-1.el9sat
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:92859
  • Red Hat Satellite 6.18 for RHEL 9 openvox-agent 8.31.1-1.el9sat
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:92860
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1791978528, rhui5/rhua-rhel9 1791978693, rhui5/haproxy-rhel9 1791978528, rhui5/installer-rhel9 1791964013, rhui5/cds-kubernetes-rhel9 1791978534
    fixed: vendor fix “Do not use trailing-dot hostnames in URLs passed to curl. Trailing dots are uncommon and incompatible with TLS SNI. Upgrade to curl 8.21.0 to resolve” RHSA-2026:82939
  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Enterprise Linux 9 rust, cargo, clippy, rustfmt, snphost, rust-gdb, +9 more Red Hat Enterprise Linux 10 igvm, rust, snphost, trustee, s390utils Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-controller-rhel9, rhoai/odh-model-serving-api-rhel9, rhoai/odh-workbenches-operator-rhel9, rhoai/odh-llama-stack-k8s-operator-rhel9, rhoai/odh-kserve-llmisvc-controller-rhel9 Red Hat Satellite 6 foreman, foreman-cli, foreman-ec2, foreman-gce, foreman-ovirt, foreman-vmware, +9 more Red Hat Satellite 6.16 for RHEL 8 openvox-server 8.17.0-1.el8sat, yggdrasil-worker-forwarder 0.1.1-1.el8sat
    +4 more products
    Red Hat Satellite 6.16 for RHEL 9 openvox-server 8.17.0-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat Red Hat Satellite 6.17 for RHEL 9 openvox-server 8.17.0-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat Red Hat Satellite 6.18 for RHEL 9 openvox-server 8.17.0-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat 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
total
Assessed
4 mo ago

Exploit prediction

0.66% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3733905 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/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-201 Insertion of Sensitive Information Into Sent Data

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.