CVE-2026-15711

Libsoup: soupwebsocketconnection: libsoup: websocket remote denial of service via oversized control frame protocol violation

Published Jul 14, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 §5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or less. A remote, unauthenticated attacker can exploit this by sending a non-compliant, oversized control frame. Because the parser handles this protocol violation improperly instead of throwing an immediate connection termination error, it triggers a internal processing crash, resulting in a remote denial of service (DoS) for applications utilizing libsoup WebSockets.

Analysis

AI-generated

Technical impact

A flaw in libsoup’s WebSocket frame parser allows a remote attacker to send a control frame with a payload larger than the 125‑byte limit defined by RFC 6455. Because the parser does not enforce this restriction, it does not terminate the connection and instead crashes internally, causing the application that uses libsoup WebSockets to stop responding. The effect is a denial of service that can be triggered without authentication from any network source that can reach the WebSocket endpoint.

Affected Systems

The vulnerability affects all Red Hat Enterprise Linux operating systems from version 6 through 10, which ship libraries that include the unpatched libsoup implementation. The issue applies to any application on those systems that utilizes libsoup for WebSocket communication.

Risk and Exploitability

The CV 7.5 indicates a high severity of the impact. The EPSS score is below 1 %, suggesting that the probability of exploitation is low at present. The vulnerability is not listed in the CISA KEV catalog. The likely attack vector is a remote, unauthenticated network user sending an oversized control frame to an exposed WebSocket service. If successful, the service will crash, denying legitimate users access until the process is restarted.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.


OpenCVE Recommended Actions

  • Upgrade the libsoup library to the latest patched version supplied by your distribution’s security updates.
  • Restart any services that use libsoup to ensure the new library is loaded.
  • No workaround currently available if immediate patching is not possible, consider temporarily restricting network access to the WebSocket endpoint from untrusted hosts.

Generated by OpenCVE AI on July 31, 2026 at 05:16 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10.3
References
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux Eus
CPEs cpe:/o:redhat:enterprise_linux_eus:10.0
Vendors & Products Redhat enterprise Linux Eus
References
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel Eus Long Life
CPEs cpe:/a:redhat:rhel_aus:8.4::appstream
cpe:/a:redhat:rhel_aus:8.6::appstream
cpe:/a:redhat:rhel_eus_long_life:8.4::appstream
cpe:/a:redhat:rhel_eus_long_life:8.6::appstream
cpe:/o:redhat:rhel_aus:8.4::baseos
cpe:/o:redhat:rhel_aus:8.6::baseos
cpe:/o:redhat:rhel_eus_long_life:8.4::baseos
cpe:/o:redhat:rhel_eus_long_life:8.6::baseos
Vendors & Products Redhat rhel Aus
Redhat rhel Eus Long Life
References
Type Values Removed Values Added
First Time appeared Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_e4s:8.8::appstream
cpe:/a:redhat:rhel_tus:8.8::appstream
cpe:/o:redhat:rhel_e4s:8.8::baseos
cpe:/o:redhat:rhel_tus:8.8::baseos
Vendors & Products Redhat rhel Tus
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_e4s:9.2::appstream
References
Type Values Removed Values Added
First Time appeared Redhat rhel E4s
CPEs cpe:/a:redhat:rhel_e4s:9.4::appstream
Vendors & Products Redhat rhel E4s
References
Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.6::appstream
Vendors & Products Redhat rhel Eus
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/a:redhat:enterprise_linux:9::appstream
cpe:/o:redhat:enterprise_linux:10.2
cpe:/o:redhat:enterprise_linux:8::baseos
References
Type Values Removed Values Added
First Time appeared Libsoup
Libsoup libsoup
Vendors & Products Libsoup
Libsoup libsoup
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 §5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or less. A remote, unauthenticated attacker can exploit this by sending a non-compliant, oversized control frame. Because the parser handles this protocol violation improperly instead of throwing an immediate connection termination error, it triggers a internal processing crash, resulting in a remote denial of service (DoS) for applications utilizing libsoup WebSockets.
Title Libsoup: soupwebsocketconnection: libsoup: websocket remote denial of service via oversized control frame protocol violation
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-770
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses
  • CWE-770

    Allocation of Resources Without Limits or Throttling

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 11, 2026, 12:57 PM
Reserved
Jul 14, 2026, 9:45 AM
Status
Deferred
Published
Jul 14, 2026, 8:16 PM
Modified
Nov 11, 2026, 1:17 PM
Severity
Moderate
Public date
Jul 14, 2026, 9:52 AM