CVE-2026-66338
🔶 mediumSummary
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 Score
5.4
Medium
EPSS Score
0.2
Exploit Probability
Published Date
2026-07-24
First Seen: 2026-07-31
📊 Relative Risk Intelligence
This CVE is Lower Risk - more severe than 22.6% of all 340,405 vulnerabilities in our database.
#263,560
Below average severity
Severity Percentile
🎯 CISA SSVC Assessment Updated: Jul 27, 2026
🔍 Exploitation Status
None
No known exploits
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Partial
Limited system impact
🏆 Discovered By
Upstream acknowledges cavid as the original reporter.
SSVC data provided by
CISA
Last Modified
2026-07-27
Source
NVD 🔗
CVSS Vector 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
CWE IDs (Weakness Types)