CVE-2026-633888.4HighCWE-617

CVE-2026-63388: Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept

libevent

Affected: libevent · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.1%probability of exploitation in the next 30 days

3rd percentile

050100

Higher than 3% of scored CVEs

8.4HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

libevent · libevent< 2.1.13; >= 2.2.0-alpha, < 2.2.2-alpha

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Reachable Assertion · Denial of Service
Vendor: libevent
Published: August 2026
Band: Unlikely (under 1%), August 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-63388 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.