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
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-14. a secondary CVSS source baseline 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(high)
- EG Risk
- 65(Attend)EG Risk 65/100SSVC: Attend
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation40% × 40%Automatability100% × 15%Action: Remediate soon — notable exploitation risk. - EPSS
- 35.2%
- KEV
- Not listed
Published
July 14, 2026
Last Modified
July 15, 2026
Advisory Details (3)
Auto-updated Jul 15, 2026WebSocket: Remote DoS via Oversized Control Frame (RFC 6455 §5.5 Violation) (#515) · Issues · GNOME / libsoup · GitLab
https://gitlab.gnome.org/GNOME/libsoup/-/issues/5152499924 – (CVE-2026-15711) CVE-2026-15711 libsoup: SoupWebsocketConnection: libsoup: WebSocket remote denial of service via oversized control frame protocol violation
https://bugzilla.redhat.com/show_bug.cgi?id=2499924Vendor Advisories for CVE-2026-15711(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- CVE-2026-15711Microsoft Security Response Center (MSRC)High
Libsoup: soupwebsocketconnection: libsoup: websocket remote denial of service via oversized control frame protocol violation
- GHSA-w948-qrw5-cffcGitHub Security AdvisoriesHigh
A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails...
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 16× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 03:05 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:30 UTCEPSS rescore
- 2026-07-19 02:28 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-17 00:19 UTCGHSA enrichment
- 2026-07-16 17:02 UTCEPSS rescore
- 2026-07-16 11:15 UTCGHSA enrichment
- 2026-07-15 22:11 UTCGHSA enrichment
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 09:07 UTCGHSA enrichment
- 2026-07-14 20:02 UTCEG score recompute
- 2026-07-14 20:01 UTCMITRE cvelistV5first tracked
Frequently asked(5)
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Dependency Blast Radius
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