CVE-2026-15711Libsoup: soupwebsocketconnection: libsoup: websocket remote denial of service via oversized control frame protocol violation

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.74% · top 45% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: poc · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Affected products

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 0:3.6.5-3.el10_2.14 – < *

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 0:3.6.6-1.el10_3.9 – < *

• Red Hat · Red Hat Enterprise Linux 10.0 Extended Update Support

  • unaffected 0:3.6.5-3.el10_0.17 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:2.62.3-15.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:2.62.3-15.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

  • unaffected 0:2.62.3-2.el8_4.10 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

  • unaffected 0:2.62.3-2.el8_4.10 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

  • unaffected 0:2.62.3-2.el8_6.10 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

  • unaffected 0:2.62.3-2.el8_6.10 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Telecommunications Update Service

  • unaffected 0:2.62.3-3.el8_8.11 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

  • unaffected 0:2.62.3-3.el8_8.11 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:2.72.0-16.el9_8.3 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:2.72.0-17.el9_9.6 – < *

• Red Hat · Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

  • unaffected 0:2.72.0-8.el9_2.13 – < *

• Red Hat · Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

  • unaffected 0:2.72.0-8.el9_4.12 – < *

• Red Hat · Red Hat Enterprise Linux 9.6 Extended Update Support

  • unaffected 0:2.72.0-10.el9_6.9 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unknown

• Red Hat · Red Hat Enterprise Linux 7

  All versions: unknown

What to do

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.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-44428 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-15711](https://cveledger.app/badge/CVE-2026-15711.svg)](https://cveledger.app/cve/CVE-2026-15711)

Record last updated 11 Nov 2026, 12:57 UTC.