GHSA-3cxm-476w-ghm2 · 深刻度： low — Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer...
Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer key is not properly checked for the subgroup membership. Impact summary: A malicious peer which presents an X9.42 key carrying the victim's p and g parameters, a forged q = r (a small prime factor of the cofactor (p−1)/q_local), and a public value Y of order r can recover the victim's private key after a small number of key exchange attempts. When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the subgroup membership check Y^q ≡ 1 (mod p) is performed using the peer's own q parameter, not the local key's q. The peer's domain parameters are then matched against the domain parameters of the private key, but the value of q is not compared. A malicious peer who presents an X9.42 key carrying the victim's p, g, a forged q = r (a small prime factor of the cofactor), and a public value Y of order r passes all checks. The shared secret then takes only r distinct values, leaking priv mod r. Repeating for each small-prime factor of the cofactor and combining via CRT recovers the full private key (Lim–Lee / small-subgroup-confinement attack). The realistic attack surface is narrow: principally CMP deployments with long-lived RA/CA DHX keys and bespoke enterprise or government applications using X9.42 DHX static keys with interactive protocols and therefore this issue was assigned Low severity. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are affected by this issue.
総合評価: CVE-2026-42770 は低リスク（20.5/100）。CVSS 深刻度は低。悪用される可能性が高い（EPSS 0.25%、16 パーセンタイル） 推奨対応: 悪用情報と EPSS の推移を監視し、必要に応じて優先度を見直してください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-18 | 0.25% | 0.25% | +0.00% |
| 2 | 2026-06-15 | 0.01% | 0.25% | +0.24% |
| 3 | 2026-06-10 | — | 0.01% | — |
EPSS の全履歴 （全 3 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 3.7 | 3.1 | LOW |
|
2.2 | 1.4 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
GHSA-3cxm-476w-ghm2 · 深刻度： low — Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer...
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2026-42770 unimportant priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2026-42770 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2026-42770 |
suse
|
medium | CVE-2026-42770 severity moderate: SUSE including 52 source package names (compat-openssl098, latest:libexpat1-2.7.1-4.1, …), 356 product×package rows across 70 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (70 product lines)): Known Not Affected 231, Fixed 69, First Fixed 56. | https://www.suse.com/security/cve/CVE-2026-42770/ |
ubuntu
|
low | CVE-2026-42770 low priority: Ubuntu including 5 source packages (edk2, nodejs, openssl, openssl-fips, openssl1.0), 35 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): not-affected 14, DNE 8, needs-triage 8, released 4, needed 1. | https://ubuntu.com/security/CVE-2026-42770 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| openssl | openssl | >= 3.0.0, < 3.0.21 | cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* |
| openssl | openssl | >= 3.4.0, < 3.4.6 | cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* |
| openssl | openssl | >= 3.5.0, < 3.5.7 | cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* |
| openssl | openssl | >= 3.6.0, < 3.6.3 | cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* |
| openssl | openssl | 4.0.0 | cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:* |