CVE-2025-11678

Stack-based Buffer Overflow in libwebsockets DNS response parsing

Published Oct 20, 2025 CVSS 4.0 · 7.5 High EPSS < 1% KEV · Not listed
Description
Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS flag is enabled during compilation, to overflow the label_stack, when the attacker is able to sniff a DNS request in order to craft a response with a matching id containing a label longer than the maximum.

Remediation

Vendor Solution

Update the library to its latest stable release, if not possible backport the fix commit 2bb9598562b37c942ba5b04bcde3f7fdf66a9d3a

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4373-1 libwebsockets security update
Ubuntu USN Ubuntu USN USN-8024-1 Libwebsockets vulnerabilities
History
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L'}

threat_severity

Important

Type Values Removed Values Added
First Time appeared Warmcat
Warmcat libwebsockets
Vendors & Products Warmcat
Warmcat libwebsockets
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS flag is enabled during compilation, to overflow the label_stack, when the attacker is able to sniff a DNS request in order to craft a response with a matching id containing a label longer than the maximum.
Title Stack-based Buffer Overflow in libwebsockets DNS response parsing
Weaknesses CWE-121
References
Metrics cvssV4_0

{'score': 7.5, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Nozomi
Published
Updated
Oct 20, 2025, 2:00 PM
Reserved
Oct 13, 2025, 9:56 AM
Status
Deferred
Published
Oct 20, 2025, 2:15 PM
Modified
Oct 8, 2026, 10:10 PM
Severity
Important
Public date
Oct 20, 2025, 1:51 PM