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Vulnerability · Published Jul 24, 2026 · Assigned by redhat

CVE-2026-66337Libsoup: libsoup: heap buffer over-read via integer underflow in soup_filter_input_stream_read_until()

Medium 6.5

In plain English

A medium-severity out-of-bounds read in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.2%top 84.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libsoup2.4no fix listedDEBIAN-CVE-2026-66337
Debian:13libsoup2.4no fix listedDEBIAN-CVE-2026-66337
Debian:12libsoup3no fix listedDEBIAN-CVE-2026-66337
Debian:13libsoup3no fix listedDEBIAN-CVE-2026-66337
Ubuntu:22.04:LTSlibsoup2.4no fix listedUBUNTU-CVE-2026-66337
Ubuntu:24.04:LTSlibsoup2.4no fix listedUBUNTU-CVE-2026-66337
Ubuntu:26.10libsoup2.4no fix listedUBUNTU-CVE-2026-66337
Ubuntu:24.04:LTSlibsoup3no fix listedUBUNTU-CVE-2026-66337
Ubuntu:26.04:LTSlibsoup3no fix listedUBUNTU-CVE-2026-66337
Ubuntu:26.10libsoup3no fix listedUBUNTU-CVE-2026-66337

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

References