Description
Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire.
Who is impacted:
* Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays
* Applications that accept user-controlled header names without case-normalization
Potential consequences:
* Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request)
* HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| undici | undici | < 6.24.0; 7.0.0 < 7.24.0 | 6.24.0: 7.24.0 |
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 | node-undici | 7.24.5+dfsg+~cs3.2.0-1 | — |
| Debian 13 | node-undici | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | node-undici | No fix yet | — |
| Ubuntu 26.04 LTS | node-undici | No fix yet | — |
| Ubuntu 25.10 | node-undici | No fix yet | — |
| Ubuntu 24.04 LTS | node-undici | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | nodejs +5 | 1:22.22.2-1.el10_1 | RHSA-2026:7080 |
| RHEL 10 | nodejs-npm | 1:10.9.7-1.22.22.2.1.el10_1 | RHSA-2026:7080 |
| RHEL 10 | nodejs24 +4 | 1:24.14.1-2.el10_1 | RHSA-2026:7675 |
| RHEL 10 | nodejs24-npm | 1:11.11.0-1.24.14.1.2.el10_1 | RHSA-2026:7675 |
| RHEL 9 | nodejs +4 | 1:22.22.2-1.module+el9.7.0+24157+8ddb2461 | RHSA-2026:7350, RHSA-2026:7302 |
| RHEL 9 | nodejs-nodemon | 3.0.1-1.module+el9.7.0+24157+8ddb2461 | RHSA-2026:7350, RHSA-2026:7302 |
| RHEL 9 | nodejs-packaging +1 | 2021.06-6.module+el9.7.0+24157+8ddb2461 | RHSA-2026:7350, RHSA-2026:7302 |
| RHEL 9 | npm | 1:10.9.7-1.22.22.2.1.module+el9.7.0+24157+8ddb2461 | RHSA-2026:7350, RHSA-2026:7302 |
| RHEL 9 | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module+el9.7.0+24157+8ddb2461 | RHSA-2026:7302 |
| RHEL 9 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module+el9.7.0+24166+51c9666b | RHSA-2026:7350 |
| RHEL 8 | nodejs +4 | 1:22.22.2-1.module+el8.10.0+24148+847b6786 | RHSA-2026:7670, RHSA-2026:7123 |
| RHEL 8 | nodejs-nodemon | 3.0.1-1.module+el8.10.0+24148+847b6786 | RHSA-2026:7670, RHSA-2026:7123 |
| RHEL 8 | nodejs-packaging +1 | 2021.06-6.module+el8.10.0+24148+847b6786 | RHSA-2026:7670, RHSA-2026:7123 |
| RHEL 8 | npm | 1:10.9.7-1.22.22.2.1.module+el8.10.0+24148+847b6786 | RHSA-2026:7670, RHSA-2026:7123 |
| RHEL 8 | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module+el8.10.0+24148+847b6786 | RHSA-2026:7123 |
| RHEL 8 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module+el8.10.0+24190+49a46c75 | RHSA-2026:7670 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | nodejs +5 | 1:22.22.2-2.el10_0 | RHSA-2026:7310 |
| RHEL 10.0 EUS | nodejs-npm | 1:10.9.7-1.22.22.2.2.el10_0 | RHSA-2026:7310 |
| RHEL 9.6 EUS | nodejs +4 | 1:22.22.2-1.module+el9.6.0+24196+39669d4e | RHSA-2026:7983 |
| RHEL 9.6 EUS | nodejs-nodemon | 3.0.1-1.module+el9.6.0+23473+45664c2d | RHSA-2026:7983 |
| RHEL 9.6 EUS | nodejs-packaging +1 | 2021.06-4.module+el9.6.0+23473+45664c2d | RHSA-2026:7983 |
| RHEL 9.6 EUS | npm | 1:10.9.7-1.22.22.2.1.module+el9.6.0+24196+39669d4e | RHSA-2026:7983 |
| RHEL 9.6 EUS | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module+el9.6.0+24196+39669d4e | RHSA-2026:7983 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | nodejs-docs | 1:22.22.2-1.el10_1 | ALSA-2026:7080 |
| AlmaLinux 10 | nodejs24-docs | 1:24.14.1-2.el10_1 | ALSA-2026:7675 |
| AlmaLinux 10 | nodejs24-npm | 1:11.11.0-1.24.14.1.2.el10_1 | ALSA-2026:7675 |
| AlmaLinux 9 | nodejs +4 | 1:24.14.1-2.module_el9.7.0+222+ef1c61e1 | ALSA-2026:7350 |
| AlmaLinux 9 | nodejs-nodemon | 3.0.3-3.module_el9.7.0+209+ecf6523e | ALSA-2026:7350 |
| AlmaLinux 9 | nodejs-packaging | 2021.06-6.module_el9.7.0+209+ecf6523e | ALSA-2026:7350 |
| AlmaLinux 9 | nodejs-packaging-bundler | 2021.06-6.module_el9.7.0+198+8bf605ba | ALSA-2026:7350 |
| AlmaLinux 9 | npm | 1:11.11.0-1.24.14.1.2.module_el9.7.0+222+ef1c61e1 | ALSA-2026:7350 |
| AlmaLinux 9 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module_el9.7.0+222+ef1c61e1 | ALSA-2026:7350 |
| AlmaLinux 8 | nodejs +4 | 1:22.22.2-1.module_el8.10.0+4158+e796f37f | ALSA-2026:7670, ALSA-2026:7123 |
| AlmaLinux 8 | nodejs-nodemon | 3.0.1-1.module_el8.10.0+4006+3c416519 | ALSA-2026:7670, ALSA-2026:7123 |
| AlmaLinux 8 | nodejs-packaging +1 | 2021.06-6.module_el8.10.0+4086+70facd4a | ALSA-2026:7670, ALSA-2026:7123 |
| AlmaLinux 8 | npm | 1:10.9.7-1.22.22.2.1.module_el8.10.0+4158+e796f37f | ALSA-2026:7670, ALSA-2026:7123 |
| AlmaLinux 8 | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module_el8.10.0+4158+e796f37f | ALSA-2026:7123 |
| AlmaLinux 8 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module_el8.10.0+4160+4819ac42 | ALSA-2026:7670 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | nodejs22 | 1:22.22.2-1.el10_1 | RLSA-2026:7080 |
| Rocky Linux 10 | nodejs24 | 1:24.14.1-2.el10_1 | RLSA-2026:7675 |
| Rocky Linux 9 | nodejs-nodemon | 3.0.1-1.module+el9.7.0+40017+f0db1785 | RLSA-2026:7350, RLSA-2026:7302 |
| Rocky Linux 9 | nodejs-packaging | 2021.06-6.module+el9.7.0+40052+e32ea525 | RLSA-2026:7350, RLSA-2026:7302 |
| Rocky Linux 8 | nodejs-nodemon | 3.0.1-1.module+el8.9.0+1760+903d54b9 | RLSA-2026:7670, RLSA-2026:7123 |
| Rocky Linux 8 | nodejs-packaging | 2021.06-6.module+el8.10.0+40048+6d99f608 | RLSA-2026:7670, RLSA-2026:7123 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | nodejs20 +4 | 1:20.20.1-1.amzn2023.0.3 | ALAS2023-2026-1524 |
| Amazon Linux 2023 | nodejs20-npm | 1:10.8.2-1.20.20.1.1.amzn2023.0.3 | ALAS2023-2026-1524 |
| Amazon Linux 2023 | nodejs22 +4 | 1:22.22.1-1.amzn2023.0.2 | ALAS2023-2026-1525 |
| Amazon Linux 2023 | nodejs22-npm | 1:10.9.4-1.22.22.1.1.amzn2023.0.2 | ALAS2023-2026-1525 |
| Amazon Linux 2023 | nodejs24 +4 | 1:24.14.0-1.amzn2023.0.2 | ALAS2023-2026-1526 |
| Amazon Linux 2023 | nodejs24-npm | 1:11.9.0-1.24.14.0.1.amzn2023.0.2 | ALAS2023-2026-1526 |
| Amazon Linux 2023 | v8-11.3-devel | 3:11.3.244.8-1.20.20.1.1.amzn2023.0.3 | ALAS2023-2026-1524 |
| Amazon Linux 2023 | v8-12.4-devel | 3:12.4.254.21-1.22.22.1.1.amzn2023.0.2 | ALAS2023-2026-1525 |
| Amazon Linux 2023 | v8-13.6-devel | 3:13.6.233.17-1.24.14.0.1.amzn2023.0.2 | ALAS2023-2026-1526 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | nodejs +4 | 1:22.22.2-1.el10_1 | ELSA-2026-7080 |
| Oracle Linux 10 | nodejs-npm | 1:10.9.7-1.22.22.2.1.el10_1 | ELSA-2026-7080 |
| Oracle Linux 10 | nodejs24 +4 | 1:24.14.1-2.0.2.el10_1 | ELSA-2026-7675 |
| Oracle Linux 10 | nodejs24-npm | 1:11.11.0-1.24.14.1.2.0.2.el10_1 | ELSA-2026-7675 |
| Oracle Linux 9 | nodejs +4 | 1:22.22.2-1.module+el9.7.0+90867+2ede48fe | ELSA-2026-7350, ELSA-2026-7302 |
| Oracle Linux 9 | nodejs-nodemon | 3.0.1-1.module+el9.7.0+90867+2ede48fe | ELSA-2026-7350, ELSA-2026-7302 |
| Oracle Linux 9 | nodejs-packaging +1 | 2021.06-6.module+el9.7.0+90866+5a953a4c | ELSA-2026-7350, ELSA-2026-7302 |
| Oracle Linux 9 | npm | 1:10.9.7-1.22.22.2.1.module+el9.7.0+90867+2ede48fe | ELSA-2026-7350, ELSA-2026-7302 |
| Oracle Linux 9 | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module+el9.7.0+90867+2ede48fe | ELSA-2026-7302 |
| Oracle Linux 9 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module+el9.7.0+90866+5a953a4c | ELSA-2026-7350 |
| Oracle Linux 8 | nodejs +4 | 1:22.22.2-1.module+el8.10.0+90865+d647ef3a | ELSA-2026-7670, ELSA-2026-7123 |
| Oracle Linux 8 | nodejs-nodemon | 3.0.1-1.module+el8.10.0+90865+d647ef3a | ELSA-2026-7670, ELSA-2026-7123 |
| Oracle Linux 8 | nodejs-packaging +1 | 2021.06-4.module+el8.10.0+90865+d647ef3a | ELSA-2026-7670, ELSA-2026-7123 |
| Oracle Linux 8 | npm | 1:10.9.7-1.22.22.2.1.module+el8.10.0+90865+d647ef3a | ELSA-2026-7670, ELSA-2026-7123 |
| Oracle Linux 8 | v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module+el8.10.0+90865+d647ef3a | ELSA-2026-7123 |
| Oracle Linux 8 | v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module+el8.10.0+90873+35652ecc | ELSA-2026-7670 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | code-server | 4.110.1-r2 | — |
| Wolfi rolling | jitsucom-jitsu-rotor +1 | 2.11.0-r17 | — |
| Wolfi rolling | langfuse-3-worker | 3.179.1-r1 | — |
| Wolfi rolling | renovate | 43.84.0-r1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | undici | < 6.24.0 | 6.24.0 | GHSA-2mjp-6q6p-2qxm |
| npm | undici | >= 7.0.0, < 7.24.0 | 7.24.0 | GHSA-2mjp-6q6p-2qxm |
Advisories 29
- ALSA-2026:7350 Important: nodejs:24 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:7675 Important: nodejs24 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:7080 Important: nodejs22 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:7123 Important: nodejs:22 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:7670 Important: nodejs:24 security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2026:7983 Red Hat Security Advisory: nodejs:22 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7675 Red Hat Security Advisory: nodejs24 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7670 Red Hat Security Advisory: nodejs:24 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7350 Red Hat Security Advisory: nodejs:24 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7302 Red Hat Security Advisory: nodejs:22 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7310 Red Hat Security Advisory: nodejs22 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7123 Red Hat Security Advisory: nodejs:22 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7080 Red Hat Security Advisory: nodejs22 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- ELSA-2026-7675 Important: nodejs24 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jun 9, 2026
- WID-SEC-2026-0933 IBM App Connect Enterprise (Hono und Undici): Mehrere Schwachstellen BSI CERT-Bund (WID) · May 31, 2026
- RLSA-2026:7675 Important: nodejs24 security update Rocky Linux Security Advisories · Apr 15, 2026
- RLSA-2026:7670 Important: nodejs:24 security update Rocky Linux Security Advisories · Apr 13, 2026
- ELSA-2026-7670 Important: nodejs:24 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 13, 2026
- RLSA-2026:7080 Important: nodejs22 security update Rocky Linux Security Advisories · Apr 12, 2026
- RLSA-2026:7350 Important: nodejs:24 security update Rocky Linux Security Advisories · Apr 10, 2026
- ELSA-2026-7350 Important: nodejs:24 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 10, 2026
- ELSA-2026-7302 Important: nodejs:22 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 10, 2026
- RLSA-2026:7302 Important: nodejs:22 security update Rocky Linux Security Advisories · Apr 9, 2026
- RLSA-2026:7123 Important: nodejs:22 security update Rocky Linux Security Advisories · Apr 9, 2026
- ELSA-2026-7123 Important: nodejs:22 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 9, 2026
- ELSA-2026-7080 Important: nodejs22 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Apr 8, 2026
- ALAS2023-2026-1524 Important: nodejs20 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 1, 2026
- ALAS2023-2026-1525 Important: nodejs22 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 1, 2026
- ALAS2023-2026-1526 Important: nodejs24 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 1, 2026