High severity · published Sep 8, 2026
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 different request boundaries, potentially…
8.3
CVSS
0.5%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EJ
Eclipse Jetty · Eclipse Foundation
12.1.0 through 12.1.11; 12.0.0 through 12.0.37; 11.0.0 through 11.0.31; 10.0.0 through 10.0.31; 9.4.0 through 9.4.63 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19203
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-19203
github.com
https://github.com/jetty/jetty.project/security/advisories/GHSA-xc35-c22g-239h
More from Eclipse Jetty
9.1
CVE-2026-10050
Digest authentication lossy encoding
9.1
CVE-2026-2332
HTTP Request Smuggling via Chunked Extension Quoted-String Parsing
8.7
CVE-2026-12611
A client may issue HTTP/2 requests to a Jetty server that result in blocking writes that are never unblocked, eventually causing all threads to be blocked and the whole server to…
8.7
CVE-2026-19204
A client may send a WebSocket frame with an unknown opcode and a very large declared payload length, causing Jetty to attempt a large memory allocation and potentially exhaust the…
8.2
CVE-2026-77711
When Jetty's `HttpClient` make a request to a server through a forward proxy, the server may reply with a 407 (Proxy Authentication Required)
