Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-66337 on Ubuntu — libsoup2.4

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Distribution advisory

This page covers CVE-2026-66337 as tracked by Ubuntu, for the package libsoup2.4. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: None.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

UBUNTU-CVE-2026-66337 is classified as CWE-125: Out-of-bounds Read. The code reads past the limits of a buffer, exposing adjacent memory contents or crashing the process.

Affected software

UBUNTU-CVE-2026-66337 is recorded against 2 packages.

  • libsoup2.4
  • libsoup3

Timeline and source

Published on 24 July 2026 and last revised on 29 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
bugzilla.redhat.com (Report)
gitlab.gnome.org (Report)
access.redhat.com (Report)

Other advisories for this package

libsoup2.4 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-125: Out-of-bounds Read) in other software:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-07-24
Updated 2026-08-20
Modified 2026-07-29
Fix URL N/A

Affected Packages

Software From version Fixed in
libsoup2.4
libsoup3

Vulnerability Monitoring

Track new vulnerabilities in libsoup2.4

UBUNTU-CVE-2026-66337 is rated CVSS 6.5 Medium. BotEraser monitors your WordPress installation and notifies you when software you use appears in our vulnerability database.

Set Up Free Alerts →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesUbuntuUbuntu 2026