CVE-2026-63387
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
Summary
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| libevent | libevent | >= 2.2.0-alpha, < 2.2.2-alpha | affected |
| libevent | libevent | < 2.1.13 | affected |
Weaknesses
- CWE-121: CWE-121: Stack-based Buffer Overflow
- CWE-193: CWE-193: Off-by-one Error
- CWE-787: CWE-787: Out-of-bounds Write
References
- https://github.com/libevent/libevent/security/advisories/GHSA-58rx-7448-jw47
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
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