WebSocket Parsing Flaw in libsoup Affects Remote Applications
CVE-2026-15711

7.5HIGH

Key Information:

Vendor

Red Hat
Status
Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Vendor
CVE Published:
14 July 2026

What is CVE-2026-15711?

A flaw exists in the WebSocket frame parsing of libsoup, where the library does not adhere to the length constraints dictated by RFC 6455 §5.5 for control frames, such as PING, PONG, and CLOSE. This oversight allows a remote, unauthenticated attacker to send oversized control frames that can trigger a failure in internal processing instead of the expected connection termination. As a result, applications that rely on libsoup for WebSocket communication can experience a denial of service (DoS), impacting their availability and functionality.

References

https://access.redhat.com/security/cve/CVE-2026-15711
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2499924
issue-trackingx_refsource_REDHAT
https://gitlab.gnome.org/GNOME/libsoup/-/issues/515

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Sebastián Alba Vives (@Sebasteuo / 0xS4bb1) for reporting this issue.
.