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Fencer Vulns
high 7.5

CVE-2026-9546 json

sending old referer

published 2026-07-03 4 mo ago modified 2026-09-15 55 d ago also EUVD-2026-41494 , GHSA-25rx-86v8-32c6 , JLSEC-2026-1221

cvss
7.5
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 vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result, the previous referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.

Patch / fix

  • julia CURL_jll 8.21.0+0
  • julia LibCURL_jll 8.21.0+0
  • curl curl 8.20.1
  • curl Debian 14 8.21.0~rc2-1

debian advisories DEBIAN-CVE-2026-9546

  • curl hummingbird 1 8.21.0-0.1.hum1
  • libcurl hummingbird 1 8.21.0-0.1.hum1
  • libcurl-minimal hummingbird 1 8.21.0-0.1.hum1
  • rust hummingbird 1 1.96.1-1.hum1
  • cargo hummingbird 1 1.96.1-1.hum1
  • clippy hummingbird 1 1.96.1-1.hum1
  • rustfmt hummingbird 1 1.96.1-1.hum1
  • rust-gdb hummingbird 1 1.96.1-1.hum1

red hat advisories RHSA-2026:29017RHSA-2026:34975

  • curl SLE Module for Basesystem 15 SP7 8.22.0-150700.7.33.1
  • curl SLES for SAP 15 SP6, SLES 15 SP6-LTSS 8.22.0-150600.4.58.1

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

  • curl openSUSE Tumbleweed 8.21.0-1.1

opensuse advisories openSUSE-SU-2026:11230-1

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

alpine advisories ALPINE-CVE-2026-9546

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

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-2026-9546 updated cvss 7.5

libcurl: libcurl: Information disclosure due to persistent Referer header

  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9, openshift-sandboxed-containers/osc-podvm-payload-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, libcurl, snphost, curl-minimal, libcurl-minimal Red Hat Enterprise Linux 10 curl, igvm, snphost
    +5 more products
    Red Hat Enterprise Linux AI (RHEL AI) 3 rust 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 Red Hat OpenShift Dev Spaces devspaces/code-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix available
  • 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 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 Enterprise Linux 8 dotnet, dotnet8.0, dotnet-host, dotnet-sdk-8.0, dotnet-hostfxr-8.0, dotnet-runtime-8.0, +10 more 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 JBoss Core Services libcurl.so, libcurl-1.dll 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
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.65% 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/3754343 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:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia CURL_jll
>=8.20.0+0, <8.21.0+0
8.21.0+0
julia LibCURL_jll
>=8.18.0+0, <8.21.0+0
8.21.0+0

Affected products

  • curl curl

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

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.