CVE-2026-66338

EUVD-2026-48752
A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.
HTTP Request/Response Smuggling
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.4 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N