CVE-2026-66338

medium

Description

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.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2506950

https://access.redhat.com/security/cve/CVE-2026-66338

Details

Source: Mitre, NVD

Published: 2026-07-24

Updated: 2026-07-24

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 5.4

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Severity: Medium

EPSS

EPSS: 0.00174