Undertow-core: undertow:http request smuggling via oversized chunk-size bit overlap
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.4%
exploitation probability
0.4%top 65% of all CVEs
observed exploitation
nono source reports it
A flaw was found in the ChunkReader component of the Undertow HTTP server, which is used by WildFly and JBoss EAP to handle chunked transfer encoding. The issue occurs because the parser uses a single internal variable to store both the remaining chunk size and state flags. By sending a specially crafted request with an extremely large chunk size, an attacker can cause these values to overlap, tricking the parser into thinking a request has finished prematurely. This can allow a second, "smuggled" request to be processed out of sync, potentially bypassing security controls.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Affected products
Red Hat · Red Hat build of Apache Camel for Spring Boot 4Red Hat · Red Hat build of Apache Camel - HawtIO 4Red Hat · Red Hat Data Grid 8Red Hat · Red Hat Enterprise Linux 10Red Hat · Red Hat Enterprise Linux 8Red Hat · Red Hat Enterprise Linux 9Red Hat · Red Hat Fuse 7Red Hat · Red Hat JBoss Enterprise Application Platform 7Red Hat · Red Hat JBoss Enterprise Application Platform 8Red Hat · Red Hat JBoss Enterprise Application Platform Expansion PackRed Hat · Red Hat Single Sign-On 7