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CVE-2026-66337VulnerabilityPublished 07/24/2026Updated 10/17/2026

Libsoup2.4: 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… (CVE-2026-66337)

Affects libsoup2.4Source GCVE Database

CVSS 3.1 base score
6.5Medium
Exploitation

Not in CISA KEV, no exploitation reported

EPSS
0.2% chance of exploitation in 30 days – higher than 14% of CVEs
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

What to do

AI-suggested

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid interacting with untrusted or malicious HTTP servers that may send crafted multipart responses.

Affected software

ProductAffectedFixed in
Ubuntu:Pro:16.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-infra-legacy/xenialOther threatsAffected
  • =2.50.0-2debian1
  • =2.52.1-1
  • =2.52.2-1
  • =2.52.2-1ubuntu0.1
  • =2.52.2-1ubuntu0.2
  • =2.52.2-1ubuntu0.3
  • =2.52.2-1ubuntu0.3+esm1
  • =2.52.2-1ubuntu0.3+esm2
  • =2.52.2-1ubuntu0.3+esm3
  • =2.52.2-1ubuntu0.3+esm4
  • =2.52.2-1ubuntu0.3+esm5
  • =2.52.2-1ubuntu0.3+esm6
  • =2.52.2-1ubuntu0.3+esm7
  • =2.52.2-1ubuntu0.3+esm8
Fixed in–
Ubuntu:Pro:18.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-infra/bionicOther threatsAffected
  • =2.60.1-1
  • =2.60.2-1
  • =2.60.2-2
  • =2.60.3-1
  • =2.61.90-1
  • =2.62.0-1
  • =2.62.1-1
  • =2.62.1-1ubuntu0.1
  • =2.62.1-1ubuntu0.3
  • =2.62.1-1ubuntu0.4
  • =2.62.1-1ubuntu0.4+esm1
  • =2.62.1-1ubuntu0.4+esm2
  • =2.62.1-1ubuntu0.4+esm3
  • =2.62.1-1ubuntu0.4+esm4
  • =2.62.1-1ubuntu0.4+esm5
  • =2.62.1-1ubuntu0.4+esm6
  • =2.62.1-1ubuntu0.4+esm7
  • =2.62.1-1ubuntu0.4+esm8
  • =2.62.1-1ubuntu0.4+esm9
Fixed in–
Ubuntu:Pro:20.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-infra/focalOther threatsAffected
  • =2.68.2-0ubuntu1
  • =2.68.2-1
  • =2.68.2-2
  • =2.68.2-2build2
  • =2.69.90-1
  • =2.70.0-1
  • =2.70.0-1ubuntu0.1
  • =2.70.0-1ubuntu0.2
  • =2.70.0-1ubuntu0.3
  • =2.70.0-1ubuntu0.4
  • =2.70.0-1ubuntu0.5
  • =2.70.0-1ubuntu0.5+esm1
  • =2.70.0-1ubuntu0.5+esm2
  • =2.70.0-1ubuntu0.5+esm3
  • =2.70.0-1ubuntu0.5+esm4
Fixed in–
Ubuntu:22.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=jammyOther threatsAffected
  • =2.72.0-3ubuntu3
  • =2.74.1-1
  • =2.74.2-2
  • =2.74.2-3
  • =2.74.2-3ubuntu0.1
  • =2.74.2-3ubuntu0.2
  • =2.74.2-3ubuntu0.3
  • =2.74.2-3ubuntu0.4
  • =2.74.2-3ubuntu0.5
  • =2.74.2-3ubuntu0.6
  • =2.74.2-3ubuntu0.7
  • =2.74.2-3ubuntu0.8
  • =2.74.2-3ubuntu0.9
Fixed in–
Ubuntu:Pro:22.04:LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=esm-apps/jammyOther threatsAffected
  • =3.0.4-2
  • =3.0.4-3
  • =3.0.5-1
  • =3.0.7-0ubuntu1
  • =3.0.7-0ubuntu1+esm1
  • =3.0.7-0ubuntu1+esm2
  • =3.0.7-0ubuntu1+esm3
  • =3.0.7-0ubuntu1+esm4
  • =3.0.7-0ubuntu1+esm5
  • =3.0.7-0ubuntu1+esm6
  • =3.0.7-0ubuntu1+esm7
  • =3.0.7-0ubuntu1+esm8
  • =3.0.7-0ubuntu1+esm9
Fixed in–
Ubuntu:24.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=nobleOther threatsAffected
  • =2.74.3-1
  • =2.74.3-2
  • =2.74.3-3
  • =2.74.3-6
  • =2.74.3-6build1
  • =2.74.3-6ubuntu1
  • =2.74.3-6ubuntu1.1
  • =2.74.3-6ubuntu1.2
  • =2.74.3-6ubuntu1.3
  • =2.74.3-6ubuntu1.4
  • =2.74.3-6ubuntu1.5
  • =2.74.3-6ubuntu1.6
  • =2.74.3-6ubuntu1.7
  • =2.74.3-6ubuntu1.8
  • =2.74.3-6ubuntu1.9
Fixed in–
Ubuntu:24.04:LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=nobleOther threatsAffected
  • =3.4.2-4
  • =3.4.4-1
  • =3.4.4-2
  • =3.4.4-4
  • =3.4.4-5
  • =3.4.4-5build1
  • =3.4.4-5build2
  • =3.4.4-5ubuntu0.1
  • =3.4.4-5ubuntu0.2
  • =3.4.4-5ubuntu0.3
  • =3.4.4-5ubuntu0.4
  • =3.4.4-5ubuntu0.5
  • =3.4.4-5ubuntu0.6
  • =3.4.4-5ubuntu0.7
  • =3.4.4-5ubuntu0.8
  • =3.4.4-5ubuntu0.9
Fixed in–
Ubuntu:26.10libsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=stonkingOther threatsAffected
  • =2.74.3-10.1ubuntu5
Fixed in–
Ubuntu:26.10libsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=stonkingOther threatsAffected
  • =3.6.6-1
Fixed in–
Ubuntu:26.04:LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=resoluteOther threatsAffected
  • =3.6.5-4
  • =3.6.5-5
  • =3.6.5-6
  • =3.6.5-7
  • =3.6.5-9
  • =3.6.6-1
  • =3.6.6-1ubuntu0.1
Fixed in–
Ubuntu:Pro:26.04:LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-apps/resoluteOther threatsAffected
  • =2.74.3-10.1ubuntu4
  • =2.74.3-10.1ubuntu5
  • =2.74.3-10.1ubuntu5+esm1
  • =2.74.3-10.1ubuntu5+esm2
  • =2.74.3-10.1ubuntu5+esm3
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

A vulnerability in libsoup2.4's soup_filter_input_stream_read_until() function causes an unsigned integer underflow, leading to a heap buffer over-read when parsing multipart HTTP responses. This flaw can be triggered by a malicious HTTP server sending crafted multipart responses, potentially causing client crashes or disclosure of sensitive heap memory. The issue affects multiple specific versions of libsoup2.4. The CVSS score is 6.5, indicating a medium severity level.

Weaknesses

References