CVE-2026-55990— Unbound 1.10.1 DNSCrypt 配置不当导致拒绝服务漏洞
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing Application新しい脆弱性情報の通知を購読するログインして購読
I. CVE-2026-55990の基本情報
脆弱性情報
脆弱性についてご質問がありますか？Shenlongの分析が参考になるかご確認ください！
Shenlongの10の質問を表示 ↗ 高度な大規模言語モデル技術を使用していますが、出力には不正確または古い情報が含まれる可能性があります。Shenlongはデータの正確性を確保するよう努めていますが、実際の状況に基づいて検証・判断してください。
脆弱性タイトル
Packet of death for a DNSCrypt misconfigured Unbound
ソース: NVD (National Vulnerability Database)
脆弱性説明
In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when the 'dnscrypt:' clause lists more 'dnscrypt-provider-cert:' files than there are matching 'dnscrypt-secret-key:' files, Unbound fills only the matched prefix and leaves the tail slots at the '0xdb' fill that libsodium's allocator writes into every allocation. Unbound would then iterate over the number of cert files, not the actual slots, so it walks into a slot with garbage data filled with '0xdb' bytes. Any unauthenticated client that sends one UDP datagram of ≥ 68 bytes whose first 8 bytes are '0xdb' to 'dnscrypt-port' will use that garbage entry which leads to a garbage dereference killing the server. This is a silent faulty configuration that goes unnoticed until triggered with the right client query. Unbound needs to be compiled with DNSCrypt support ('--enable-dnscrypt').
ソース: NVD (National Vulnerability Database)
CVSS情報
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
ソース: NVD (National Vulnerability Database)
脆弱性タイプ
使用未经初始化的变量
ソース: NVD (National Vulnerability Database)
影響を受ける製品
| ベンダー | プロダクト | 影響を受けるバージョン | CPE | 購読 |
|---|---|---|---|---|
| NLnet Labs | Unbound | 1.7.0 ~ 1.25.2 | - |
II. CVE-2026-55990の公開POC
| # | POC説明 | ソースリンク | Shenlongリンク |
|---|
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CVE-2026-55990 新闻报道 (1)
Same Patch Batch · NLnet Labs · 2026-07-22 · 24 CVEs total
| CVE-2026-55973 | 7.5 HIGH | 'dns-error-reporting: yes' leads to stack buffer overflow |
| CVE-2026-44690 | 7.5 HIGH | Cross-zone wildcard cache poisoning via RRSIG.labels manipulation |
| CVE-2026-32665 | 7.5 HIGH | Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass |
| CVE-2026-40691 | 7.5 HIGH | Packet of death for DNSCrypt over TCP |
| CVE-2026-50248 | 6.5 MEDIUM | BOGUS configured primary hostname accepted for XFR in auth/rpz zones |
| CVE-2026-50046 | 5.9 MEDIUM | Possible heap use-after-free in an error path when a DoT forwarded query is jostled out |
| CVE-2026-55717 | 5.9 MEDIUM | 'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash |
| CVE-2026-55991 | 5.9 MEDIUM | Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2 |
| CVE-2026-56444 | 5.9 MEDIUM | Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-timeout |
| CVE-2026-44621 | 5.9 MEDIUM | Libunbound applications configured with 'unwanted-reply-threshold' could eventually be abr |
| CVE-2026-52863 | 5.9 MEDIUM | Memory corruption could lead to crash and denial of service |
| CVE-2026-14586 | 5.9 MEDIUM | Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments |
| CVE-2026-50251 | 5.3 MEDIUM | Attacker supplied '0.0.0.0'/'::' glue triggers defensive full-cache flush |
| CVE-2026-50045 | 5.3 MEDIUM | 'max-global-quota' reset by DNSSEC validation restarts |
| CVE-2026-56416 | 4.8 MEDIUM | Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name |
| CVE-2026-42955 | 3.7 LOW | Extra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a one-tim |
| CVE-2026-54478 | 3.7 LOW | DNS Cookie bypass when combined with proxy-protocol use |
| CVE-2026-44687 | 3.7 LOW | Off-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by a legi |
| CVE-2026-46582 | 3.7 LOW | A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply |
| CVE-2026-41637 | 3.7 LOW | Degradation of resolution service from improperly accounted client-terminated DNS-over-QUI |
Showing 20 of 24 CVEs. View all on vendor page →
IV. 関連脆弱性
同じ製品: Unbound
- CVE-2026-56444
Degradation of resolution service when 'discard-timeout' and - CVE-2026-56416
Possible heap buffer overflow when validator canonicalizes R - CVE-2026-55991
Remote DNS-over-QUIC (DoQ) flow-control assertion failure in - CVE-2026-55973
'dns-error-reporting: yes' leads to stack buffer overflow - CVE-2026-55717
'serve-expired-client-timeout' and 'response-ip' CNAME redir
同じベンダー: NLnet Labs
- CVE-2026-56444
Degradation of resolution service when 'discard-timeout' and - CVE-2026-56416
Possible heap buffer overflow when validator canonicalizes R - CVE-2026-55991
Remote DNS-over-QUIC (DoQ) flow-control assertion failure in - CVE-2026-55973
'dns-error-reporting: yes' leads to stack buffer overflow - CVE-2026-55717
'serve-expired-client-timeout' and 'response-ip' CNAME redir
V. CVE-2026-55990へのコメント
まだコメントはありません