CVE-2026-56416
Açıklama (NVD)
In NLnet Labs Unbound up to and including version 1.25.1, when the validator builds the canonical RDATA form for an RRSIG-covered PX/RP/MINFO/SOA RRset, it computes the address of the second embedded domain name as 'datstart + dname_valid(datstart, ...)' and passes it straight to 'query_dname_tolower()' without checking that a second name is actually present in the RDATA. The wire-format parser accepts multi-dname RRs whose RDATA ends after the first name, so an attacker who runs a DNSSEC-signed authoritative server can deliver a record with an absent second domain name (e.g. SOA record) and cause 'query_dname_tolower()' to walk label-by-label through stale bytes in the per-worker 'env->scratch_buffer', past the end of that heap allocation if 'msg-buffer-size' has been lowered from the default. This leads to heap buffer overflow and on a release build the outcome relies heavily on the contents of the buffer tail and the adjacent heap chunk.
Yayın: 22.07.2026 · Son değişiklik: 24.10.2026 · Zayıflık: CWE-354
CVSS 3.1 metrikleri
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
| Saldırı vektörü | Ağ (uzaktan) |
| Karmaşıklık | Yüksek |
| Gereken yetki | Yok |
| Kullanıcı etkileşimi | Gerekmez |
| Kapsam | Değişmez |
| Gizlilik | Yok |
| Bütünlük | Düşük |
| Erişilebilirlik | Düşük |
Hesaplanan temel puan: 4.8. CVSS hesaplayıcıda incele