Description
Apache Traffic Server does not reject Transfer-Encoding in HTTP/2 requests, allowing downgrade request smuggling.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.
Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache Traffic Server | 8.0.0 – ≤ 8.1.11, 9.0.0 – ≤ 9.2.14, 10.0.0 – ≤ 10.1.3 | — |
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 12 | trafficserver | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | trafficserver | No fix yet | — |
| Ubuntu 18.04 LTS | trafficserver | No fix yet | — |
| Ubuntu 16.04 LTS | trafficserver | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | trafficserver | No fix yet | — |
| Ubuntu Pro 20.04 LTS | trafficserver | No fix yet | — |
Advisories 1
- WID-SEC-2026-2561 Apache Traffic Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 29, 2026
References
- https://lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d vendor-advisory