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Fencer Vulns
critical 9.8

CVE-2026-11856 json

cross-origin Digest auth state leak

published 2026-07-03 4 mo ago modified 2026-09-15 55 d ago also EUVD-2026-41501 , GHSA-9crq-qh8v-6xmm , JLSEC-2026-1201

cvss
9.8
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 52%
public exploits
0
none known

Summary

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

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 14 8.21.0~rc3-1

debian advisories DEBIAN-CVE-2026-11856

  • curl Ubuntu 22.04 LTS 7.81.0-1ubuntu1.26
  • curl Ubuntu 24.04 LTS 8.5.0-2ubuntu10.12
  • curl Ubuntu 26.04 LTS 8.18.0-1ubuntu2.4
  • curl Ubuntu Pro 14.04 LTS 7.35.0-1ubuntu2.20+esm22
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm18
  • curl Ubuntu Pro 18.04 LTS 7.58.0-2ubuntu3.24+esm11
  • curl Ubuntu Pro 20.04 LTS 7.68.0-1ubuntu2.25+esm6

ubuntu advisories UBUNTU-CVE-2026-11856

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 SLE Module for Basesystem 15 SP7 8.22.0-150700.7.33.1
  • curl SLES 15 SP5-LTSS, SLES 15 SP4-LTSS, SLE Micro 5.5 +8 more 8.14.1-150400.5.98.1
  • curl SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 8.0.1-11.134.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.22.0-150600.4.58.1

suse advisories SUSE-SU-2026:5071-1SUSE-SU-2026:5069-1SUSE-SU-2026:5068-1SUSE-SU-2026:4954-1

  • curl openSUSE Tumbleweed 8.21.0-1.1

opensuse advisories openSUSE-SU-2026:11230-1

  • 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 3.23 8.22.0-r0
  • curl Alpine 3.24 8.21.0-r0

alpine advisories ALPINE-CVE-2026-11856

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 8.11.1-11
  • cmake Azure Linux 3.0 3.30.3-15

azure linux advisories AZL-91803AZL-91830

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-2026-11856 updated cvss 6.5

curl: curl: Information disclosure via incorrect Digest authentication header reuse

  • Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 7 curl, libcurl
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1791460851
    fixed: vendor fix 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 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 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 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_10.18, libcurl 7.61.1-34.el8_10.18, libcurl-minimal 7.61.1-34.el8_10.18
    fixed: vendor fix RHSA-2026:92368
show 8 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 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 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 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 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 RHSA-2026:82939
  • 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 OpenShift Dev Spaces devspaces/code-rhel9 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 ICSA-26-293-05 updated cvss 8.1

Hitachi Energy RTU500 Product

  • Hitachi Energy RTU500 series CMU Firmware vers:RTU500_series_CMU_Firmware/>=13.5.1, <=13.5.4, vers:RTU500_series_CMU_Firmware/>=13.6.1, <=13.6.3, vers:RTU500_series_CMU_Firmware/>=13.7.1, <=13.7.8, vers:RTU500_series_CMU_Firmware/>=13.8.1, <=13.8.2
    affected: vendor fix, mitigation

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3793260 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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-294 Authentication Bypass by Capture-replay

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.