CVE-2025-11678 Stack-based Buffer Overflow in libwebsockets DNS response parsing
A stack-based buffer overflow in libwebsockets allows attackers to execute code or cause denial of service via crafted DNS responses when async DNS is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-11678?
CVE-2025-11678 is a high-severity memory corruption vulnerability in warmcat libwebsocket, published on 20 Oct 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-121
Which versions are affected by CVE-2025-11678?
Linux distribution packages (4)
libwebsockets Red Hat:openstack:17.1::el9 | All versions | 0:4.3.0-2.el9ost |
libwebsockets-debuginfo Red Hat:openstack:17.1::el9 | All versions | 0:4.3.0-2.el9ost |
libwebsockets-debugsource Red Hat:openstack:17.1::el9 | All versions | 0:4.3.0-2.el9ost |
libwebsockets-devel-debuginfo Red Hat:openstack:17.1::el9 | All versions | 0:4.3.0-2.el9ost |
How do I fix CVE-2025-11678?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-11678 being exploited?
There is no known exploitation of CVE-2025-11678 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-11678, DEBIAN-CVE-2025-11678, GHSA-2g39-f45w-2fcm, RHSA-2025:22969, UBUNTU-CVE-2025-11678.