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
HIGHPre-NVD 7.57.5—Trending — 4 sources updated this weekElevated
EchelonGraph scoreHIGH confidence
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.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0
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)
- EPSS
- 34.9%
- KEV
- Not listed
Published
July 14, 2026
Last Modified
July 15, 2026
Advisory Details (3)
Auto-updated Jul 15, 2026🔬 Proof of concept available. Patch available. Sources: redhat.
generic🟡 PoC Available
WebSocket: Remote DoS via Oversized Control Frame (RFC 6455 §5.5 Violation) (#515) · Issues · GNOME / libsoup · GitLab
https://gitlab.gnome.org/GNOME/libsoup/-/issues/515redhat
2499924 – (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(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 7× 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.
- 2026-07-15 22:11 UTCEG score recompute
- 2026-07-15 22:11 UTCGHSA enrichment
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 09:07 UTCEG score recompute
- 2026-07-15 09:07 UTCGHSA enrichment
- 2026-07-14 20:02 UTCEG score recompute
- 2026-07-14 20:01 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-15711?
CVE-2026-15711 is a high vulnerability published on July 14, 2026. 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…
When was CVE-2026-15711 disclosed?
CVE-2026-15711 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15711 actively exploited?
CVE-2026-15711 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-15711?
CVE-2026-15711 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-15711?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15711, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-15711
Is Your Infrastructure Affected by CVE-2026-15711?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.