Search/CVE-2026-66338
CVE — Medium

CVE-2026-66338

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.

CVSS v3.1
5.4 MEDIUM
EPSS
0.19%
probability of exploitation in 30 days
CISA KEV
Not listed
no confirmed exploitation reported
News coverage
0
sources referencing this CVE
Intelligence Reports1
1 intelligence report available

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CVSS v3.1 Detail
Attack VectorNETWORK
Attack ComplexityHIGH
Privileges RequiredNONE
User InteractionNONE
ScopeCHANGED
ConfidentialityLOW
IntegrityLOW
AvailabilityNONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
Connections
3 relationships
Timeline
disclosure → media coverage
Jul 24, 2026
Disclosure — published as a CVE record.