Non-CA certificate accepted as intermediate issuer in public_key path validation
CVSS Skor
7.0
EPSS İhtimal
%0.4
Risk Skoru
0.0
Yayın
4 ay önce
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Zafiyet Açıklaması
DayBreach CVE AI Araştırması
CVE-2026-42789 için toplanan üretici, dağıtım, yama ve güvenlik kaynağı kayıtlarını karşılaştırıp kanıt bağlantılı bir açıklama hazırlayalım.
Improper Following of a Certificate's Chain of Trust vulnerability in Erlang OTP public_key (pubkey_cert module) allows a non-CA certificate to be accepted as an intermediate issuer, enabling certificate chain forgery. In lib/public_key/src/pubkey_cert.erl, pubkey_cert:validate_extensions/7 contains two flaws that together allow a certificate with basicConstraints cA:false and no keyUsage extension to be used as an intermediate issuer in a chain passed to public_key:pkix_path_validation/3: the cA:false clause recurses into the remaining extensions without rejecting the certificate when it is in issuer position, and the keyUsage check only fires when the extension is present, so a certificate lacking keyUsage entirely bypasses the keyCertSign enforcement. Any party holding an end-entity certificate with basicConstraints cA:false and no keyUsage extension, issued by any CA in the victim's trust store, can use that certificate's private key to sign forged leaf certificates for arbitrary identities. public_key:pkix_path_validation/3 accepts the resulting chain, and by extension every TLS or mTLS endpoint built on the OTP ssl application that relies on the default verifier is affected, including server identity verification on the client side and client certificate verification on mTLS servers. This issue affects OTP from OTP 17.0 before OTP 26.2.5.21, OTP 27.3.4.12, OTP 28.5.0.1, and OTP 29.0.1, corresponding to public_key from 0.22 before 1.15.1.7, 1.17.1.3, 1.20.3.1, and 1.21.1. Whether OTP before OTP 17.0, corresponding to public_key before 0.22, is affected is unknown.
IMPACT — Etkilenen Ürünler ve Yazılımlar
Affected Products
The following products are affected by CVE-2026-42789 vulnerability. Even if our threat engine is aware of the exact versions of the products that are affected, the information is represented below.
RED HAT CSAF/VEX — Ürün Etki Kontrolü
SCORING — CVSS Çoklu Kaynak Skoru
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from various sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 8.0 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N | NVD |
| 8.0 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N | CVE ADP |
| 7.0 | CVSS V40 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD |
| 7.0 | CVSS V4_0 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N | CVE CNA |
| 4.8 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N | NVD |
Yama ve İyileştirme Rehberi (Solution)
Solution & Remediation Advisory
7 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.
Public exploit ve aktif sömürü durumu
Doğrulanmış exploit istihbaratı
Bu CVE için henüz doğrulanmış public PoC, exploit repository’si veya Metasploit modülü bulunamadı.
Zafiyet Dağılımı ve Saldırı Kalıpları (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-42789 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-42789 weaknesses.
Saldırı Vektörü ve Erişilebilirlik Karakteristiği
Resmi Kaynaklar ve Danışma Bültenleri
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curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-42789"