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Fencer Vulns
medium 5.4

CVE-2026-58055 json

nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length

published 2026-06-28 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-39975 , GHSA-xrr7-82jr-v58x , JLSEC-2026-1157

cvss
5.4
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 16%
public exploits
0
none known

Summary

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.

Patch / fix

  • julia nghttp2_jll 1.70.0+0
  • nghttp2 Debian 14 1.70.0-1

debian advisories DEBIAN-CVE-2026-58055

  • nghttp2 Ubuntu 22.04 LTS 1.43.0-1ubuntu0.4
  • nghttp2 Ubuntu 24.04 LTS 1.59.0-1ubuntu0.4
  • nghttp2 Ubuntu 25.10 1.64.0-1.1ubuntu1.2
  • nghttp2 Ubuntu 26.04 LTS 1.68.0-2ubuntu0.2

ubuntu advisories UBUNTU-CVE-2026-58055

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

  • nghttp2 RHEL 8 1.33.0-6.el8_10.3
  • libnghttp2 RHEL 8 1.33.0-6.el8_10.3
  • nghttp2 RHEL 9 1.43.0-6.el9_8.2
  • libnghttp2 RHEL 9 1.43.0-6.el9_8.2
  • nghttp2 RHEL 10.2 1.68.0-3.el10_2.2
  • libnghttp2 RHEL 10.2 1.68.0-3.el10_2.2
  • nghttp2 hummingbird 1 1.69.0-5.hum1
  • libnghttp2 hummingbird 1 1.69.0-5.hum1

red hat advisories RHSA-2026:55804RHSA-2026:54662RHSA-2026:54650RHSA-2026:52414RHSA-2026:41240RHSA-2026:35454

  • nghttp2 SLE Module for Basesystem 15 SP7 1.64.0-150700.3.6.1
  • nghttp2 Linux Micro 6.1 1.52.0-slfo.1.1_3.1
  • nghttp2 SLE Module for Basesystem 15 SP7 1.40.0-150600.25.8.1
  • nghttp2 SLE Micro 5.5, SLE Micro 5.4, SLE Micro 5.3 1.40.0-150200.25.1
  • nghttp2 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.64.0-160000.4.1
  • nghttp2 Linux Micro 6.0 1.52.0-7.1
  • nghttp2 SLES LTSS Extended Security 12 SP5 1.39.2-3.26.1

suse advisories SUSE-SU-2026:4029-1SUSE-SU-2026:22893-1SUSE-SU-2026:3154-1SUSE-SU-2026:3153-1SUSE-SU-2026:2883-1SUSE-SU-2026:22594-1

  • nghttp2 openSUSE Leap 16.0 1.64.0-160000.4.1
  • nghttp2 openSUSE Tumbleweed 1.69.0-2.1

opensuse advisories openSUSE-SU-2026:21302-1openSUSE-SU-2026:11156-1

  • nghttp2 AlmaLinux 8 1.33.0-6.el8_10.3
  • libnghttp2 AlmaLinux 8 1.33.0-6.el8_10.3
  • nghttp2 AlmaLinux 10 1.68.0-3.el10_2.2
  • libnghttp2 AlmaLinux 10 1.68.0-3.el10_2.2
  • nghttp2 AlmaLinux 9 1.43.0-6.el9_8.2
  • libnghttp2 AlmaLinux 9 1.43.0-6.el9_8.2

almalinux advisories ALSA-2026:55804ALSA-2026:54650ALSA-2026:54662

  • nghttp2 Rocky Linux 8 1.33.0-6.el8_10.3
  • nghttp2 Rocky Linux 10 1.68.0-3.el10_2.2
  • nghttp2 Rocky Linux 9 1.43.0-6.el9_8.2

rocky linux advisories RLSA-2026:55804RLSA-2026:54650RLSA-2026:54662

  • nghttp2 Alpine 3.24 1.70.0-r0

alpine advisories ALPINE-CVE-2026-58055

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

  • fluent-bit Azure Linux 3.0 3.1.10-6

azure linux advisories AZL-91451

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-2026-58055 updated cvss 5.4

nghttp2: nghttp2: HTTP Request/Response Smuggling and Response-Queue Poisoning via ambiguous HTTP/1.1 Upgrade requests

  • Red Hat Enterprise Linux 8 npm, nodejs, nodejs-libs, nodejs-nodemon, nodejs-full-i18n, nodejs-packaging, +1 more Red Hat Enterprise Linux 9 npm, nodejs, nodejs-libs, nodejs-full-i18n Red Hat Enterprise Linux 10 nodejs22, nodejs24 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 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. 10) libnghttp2-devel 1.68.0-3.el10_2.2, nghttp2-debuginfo 1.68.0-3.el10_2.2, nghttp2-debugsource 1.68.0-3.el10_2.2, libnghttp2-debuginfo 1.68.0-3.el10_2.2
    fixed: vendor fix RHSA-2026:54650
  • Red Hat Enterprise Linux BaseOS (v. 8) nghttp2 1.33.0-6.el8_10.3, libnghttp2 1.33.0-6.el8_10.3
    fixed: vendor fix RHSA-2026:55804
show 8 more
  • Red Hat Enterprise Linux BaseOS (v. 9) nghttp2 1.43.0-6.el9_8.2, libnghttp2 1.43.0-6.el9_8.2
    fixed: vendor fix RHSA-2026:54662
  • Red Hat Enterprise Linux BaseOS (v. 10) nghttp2 1.68.0-3.el10_2.2, libnghttp2 1.68.0-3.el10_2.2
    fixed: vendor fix RHSA-2026:54650
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nghttp2 1.43.0-6.el9_8.2
    fixed: vendor fix RHSA-2026:54662
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nghttp2 1.68.0-3.el10_2.2
    fixed: vendor fix RHSA-2026:54650
  • Red Hat Enterprise Linux CRB (v. 8) nghttp2 1.33.0-6.el8_10.3
    fixed: vendor fix RHSA-2026:55804
  • Red Hat Hardened Images nghttp2 1.69.0-5.hum1, curl 8.21.0-0.1.1.hum1, nghttp2 1.69.0-3.1.hum1, nghttp2 1.70.0-0.1.hum1, libnghttp2 1.69.0-5.hum1, libcurl 8.21.0-0.1.1.hum1, +9 more
    fixed: vendor fix RHSA-2026:41240
  • 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 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
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/bikini/exploitarium/tree/main/nghttp2-nghttpx-upgrade-queue-poison-poc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
julia nghttp2_jll
<1.70.0+0
1.70.0+0

Affected products

  • nghttp2 nghttp2

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

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.