Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nghttp2 | nghttp2 | ≤ 1.69.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | nghttp2 | 1.70.0-1 | — |
| Debian 13 | nghttp2 | No fix yet | — |
| Debian 12 | nghttp2 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | nghttp2 | 1.68.0-2ubuntu0.2 | USN-8495-1 |
| Ubuntu 25.10 | nghttp2 | 1.64.0-1.1ubuntu1.2 | USN-8495-1 |
| Ubuntu 24.04 LTS | nghttp2 | 1.59.0-1ubuntu0.4 | USN-8495-1 |
| Ubuntu 22.04 LTS | nghttp2 | 1.43.0-1ubuntu0.4 | USN-8495-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | nghttp2 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | nghttp2 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | nghttp2 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | nghttp2 +2 | 1.68.0-3.el10_2.2 | RHSA-2026:54650 |
| RHEL 9 | nghttp2 +2 | 1.43.0-6.el9_8.2 | RHSA-2026:54662 |
| RHEL 8 | nghttp2 +2 | 1.33.0-6.el8_10.3 | RHSA-2026:55804 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | curl +3 | 8.21.0-0.1.1.hum1 | RHSA-2026:41240 |
| Red Hat Hardened Images 1 | nghttp2 +4 | 1.69.0-3.1.hum1 | RHSA-2026:86895, RHSA-2026:52414, RHSA-2026:35454 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | nghttp2 +2 | 1.68.0-3.el10_2.2 | ALSA-2026:54650 |
| AlmaLinux 9 | nghttp2 +2 | 1.43.0-6.el9_8.2 | ALSA-2026:54662 |
| AlmaLinux 8 | nghttp2 +2 | 1.33.0-6.el8_10.3 | ALSA-2026:55804 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | nghttp2 | 1.68.0-3.el10_2.2 | RLSA-2026:54650 |
| Rocky Linux 9 | nghttp2 | 1.43.0-6.el9_8.2 | RLSA-2026:54662 |
| Rocky Linux 8 | nghttp2 | 1.33.0-6.el8_10.3 | RLSA-2026:55804 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | nghttp2 | 1.40.0-150600.25.8.1 | SUSE-SU-2026:4029-1, SUSE-SU-2026:3153-1 |
| SLES 12 SP5 | nghttp2 | 1.39.2-3.26.1 | SUSE-SU-2026:3154-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | nghttp2 | 1.64.0-160000.4.1 | SUSE-SU-2026:22630-1 |
| SLES 16.0 | nghttp2 | 1.64.0-160000.4.1 | SUSE-SU-2026:22630-1 |
| SLE Micro 6.2 | nghttp2 | 1.64.0-160000.4.1 | SUSE-SU-2026:22594-1 |
| SLE Micro 6.1 | nghttp2 | 1.52.0-slfo.1.1_3.1 | SUSE-SU-2026:22893-1 |
| SLE Micro 6.0 | nghttp2 | 1.52.0-7.1 | SUSE-SU-2026:22707-1 |
| SLE Micro 5.5 | nghttp2 | 1.40.0-150200.25.1 | SUSE-SU-2026:2883-1 |
| SLE Micro 5.4 | nghttp2 | 1.40.0-150200.25.1 | SUSE-SU-2026:2883-1 |
| SLE Micro 5.3 | nghttp2 | 1.40.0-150200.25.1 | SUSE-SU-2026:2883-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | nghttp2 | 1.69.0-2.1 | openSUSE-SU-2026:11156-1 |
| openSUSE Leap 16.0 | nghttp2 | 1.64.0-160000.4.1 | openSUSE-SU-2026:21302-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | nghttp2 | 1.70.0-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | fluent-bit | 3.1.10-6 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | nghttp2 +2 | 1.68.0-3.el10_2.2 | ELSA-2026-54650 |
| Oracle Linux 9 | nghttp2 +2 | 1.43.0-6.el9_8.2 | ELSA-2026-54662 |
| Oracle Linux 8 | nghttp2 +2 | 1.33.0-6.el8_10.3 | ELSA-2026-55804 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | nghttp2 +3 | 1.70.0-r0 | — |
Advisories 29
- RHSA-2026:86895 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-3595 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- WID-SEC-2026-2110 nghttp2: Schwachstelle ermöglicht Manipulation von Daten BSI CERT-Bund (WID) · Oct 29, 2026
- ALSA-2026:54662 Moderate: nghttp2 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:54650 Moderate: nghttp2 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:55804 Moderate: nghttp2 security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2026:41240 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:55804 Red Hat Security Advisory: nghttp2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:54650 Red Hat Security Advisory: nghttp2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:54662 Red Hat Security Advisory: nghttp2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:52414 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:35454 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- SUSE-SU-2026:4029-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Sep 13, 2026
- RLSA-2026:55804 Moderate: nghttp2 security update Rocky Linux Security Advisories · Aug 18, 2026
- ELSA-2026-55804 Moderate: nghttp2 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 18, 2026
- RLSA-2026:54650 Moderate: nghttp2 security update Rocky Linux Security Advisories · Aug 14, 2026
- RLSA-2026:54662 Moderate: nghttp2 security update Rocky Linux Security Advisories · Aug 14, 2026
- ELSA-2026-54650 Moderate: nghttp2 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 13, 2026
- ELSA-2026-54662 Moderate: nghttp2 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 13, 2026
- SUSE-SU-2026:22893-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 28, 2026
- SUSE-SU-2026:22707-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 23, 2026
- SUSE-SU-2026:3153-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 22, 2026
- SUSE-SU-2026:3154-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 22, 2026
- SUSE-SU-2026:22630-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 17, 2026
- SUSE-SU-2026:22594-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 16, 2026
- SUSE-SU-2026:2883-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 14, 2026
- openSUSE-SU-2026:21302-1 Security update for nghttp2 SUSE / openSUSE Security Updates · Jul 13, 2026
- USN-8495-1 nghttp2 vulnerability Ubuntu Security Notices (USN) · Jul 2, 2026
- openSUSE-SU-2026:11156-1 libnghttp2-14-1.69.0-2.1 on GA media SUSE / openSUSE Security Updates · Jul 1, 2026
References
- Proof of Concept exploit third-party-advisory
- Fix commit (master) patch
- VulnCheck Advisory: nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length third-party-advisory