CVE-2026-66337

Libsoup: libsoup: heap buffer over-read via integer underflow in soup_filter_input_stream_read_until()

MEDIUM
6.5
CVSS Score
Published: July 24, 2026 at 11:01 PM UTC
Updated: August 24, 2026 at 05:01 PM UTC
2 products affected across 2 vendorsEnterprise LinuxLibsoup

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

VDB Entryx_refsource_REDHATVendor Advisory
https://access.redhat.com/security/cve/CVE-2026-66337
Issue Trackingx_refsource_REDHATExploitVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2506949

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125

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