Description
httpd function check_header/3 rejects duplicate Content-Length (per CVE-2026-23941) but never checks for the TE+CL co-presence that RFC 9112 §6.3 identifies as a probable smuggling attempt. handle_body/3 frames by chunked and silently discards Content-Length. A CL-preferring front-end paired with chunked-preferring inets creates a classic CL.TE front-end/back-end desync.
This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, OTP 28.5.0.6, and OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, 9.6.2.3, and 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Erlang | OTP | 17.0, 5.10 | — |
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 | erlang | 1:29.0.6+dfsg-1 | — |
| Debian 13 | erlang | 1:27.3.4.1+dfsg-1+deb13u4 | — |
| Debian 12 | erlang | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | erlang | 1:27.3.4.6+dfsg-1ubuntu0.1 | USN-8827-1 |
| Ubuntu 24.04 LTS | erlang | 1:25.3.2.8+dfsg-1ubuntu4.7 | USN-8827-1 |
| Ubuntu 22.04 LTS | erlang | 1:24.2.1+dfsg-1ubuntu0.7 | USN-8827-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | erlang | 1:22.2.7+dfsg-1ubuntu0.5+esm2 | USN-8827-1 |
| Ubuntu Pro 18.04 LTS | erlang | 1:20.2.2+dfsg-1ubuntu2+esm3 | USN-8827-1 |
| Ubuntu Pro 16.04 LTS | erlang | 1:18.3-dfsg-1ubuntu3.1+esm3 | USN-8827-1 |
| Ubuntu Pro 14.04 LTS | erlang | 1:16.b.3-dfsg-1ubuntu2.2+esm2 | USN-8827-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | erlang27 +38 | 27.3.4.17-0.1.hum1 | RHSA-2026:62531 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | erlang | 26.2.5.21-6 | — |
Advisories 3
- WID-SEC-2026-3146 Erlang/OTP: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- RHSA-2026:62531 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 2, 2026
- USN-8827-1 erlang vulnerabilities Ubuntu Security Notices (USN) · Sep 28, 2026