HIGH

CVE-2026-15711

CVSS v3

7.5

HIGH

EPSS Score

0.7 %

exploit probability, as of 2026-10-19

CISA KEV

known exploited

Exploitation

—

SSVC status

Get an alert for each new CVE published for libsoup.

Set up CVE WatchFree account · no credit card

Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

libsoupAlmaLinux:9all versions · fixed in 2.72.0-16.el9_8.3and 1 other package
libsoupAlmaLinux:8all versions · fixed in 2.62.3-15.el8_10and 1 other package
libsoup3AlmaLinux:10all versions · fixed in 3.6.5-3.el10_2.14and 2 other packages

Vendor advisories

CVE-2026-15711 Red Hat Product Security271 products fixed · 6 known affected
libsoup: SoupWebsocketConnection: libsoup: WebSocket remote denial of service via oversized control frame protocol violation
libsoup as a component of Red Hat Enterprise Linux 6 · libsoup-devel as a component of Red Hat Enterprise Linux 6 · libsoup.src as a component of Red Hat Enterprise Linux 6
RHSA-2026:71389 Red Hat Product Security18 products fixed
Red Hat Security Advisory: libsoup3 security update
RHSA-2026:70598 Red Hat Product Security44 products fixed
Red Hat Security Advisory: libsoup security update
RHSA-2026:70599 Red Hat Product Security44 products fixed
Red Hat Security Advisory: libsoup security update
RHSA-2026:69863 Red Hat Product Security32 products fixed
Red Hat Security Advisory: libsoup security update
RHSA-2026:69297 Red Hat Product Security21 products fixed
Red Hat Security Advisory: libsoup security update

5 more advisories

Full record on NVD

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.

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2026-07-14
Last Modified: 2026-07-15

Frequently asked questions

What is CVE-2026-15711?

Is CVE-2026-15711 actively exploited?

Active exploitation of CVE-2026-15711 has not been confirmed. Its EPSS score was 0.7% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-15711?

CVE-2026-15711 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running libsoup? Hear about its next vulnerability

CVE Watch matches each new CVE to the vendors and products you list (vendor and product, not the version) and puts it in your alerts with its KEV and EPSS status.

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

Already have an account? Open CVE WatchNo credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? CVE Watch alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database