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.

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0780 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2026-15711:
    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.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0779 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2026-15711:
    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.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-15711)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
331812	TencentOS Server 4: libsoup (TSSA-2026:0780)	Nessus	Tencent Local Security Checks	high
331811	TencentOS Server 4: libsoup3 (TSSA-2026:0779)	Nessus	Tencent Local Security Checks	high
326909	Linux Distros Unpatched Vulnerability : CVE-2026-15711	Nessus	Misc.	high

Detections

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CVE-2026-15711

high

Tenable Plugins

high

high

high