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CVE-2026-42769

Improper certificate validation in Openssl

CVSS score

5.3

EPSS probability

%0.2

Risk score

0.0

Published

4 mo ago

Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-42769 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

Issue Summary: An error in the callback used to verify the certificate provided in a Root CA key update Certificate Management Protocol (CMP) message response rendered the certificate validation ineffectual, which could lead to escalation of credentials from the Registration Authority (RA) level to the root Certification Authority (root CA) level. Impact Summary: The Registration Autority could replace the root CA certificate for the CMP clients with an arbitrary root CA certificate. One of the parts of the Certificate Management Protocol (CMP), specified in RFC 9810, is Root Certification Authority (root CA) key Rollover, which is sent by the server in a message with type 'id-it-rootCaKeyUpdate'. As part of these messages, 'newWithOld' certificate, the new root CA certificate signed with the old root CA key, is provided, and verifying its signature is crucial for transferring the trust from the old CA key to the new one. The 'id-it-rootCaKeyUpdate' messages are expected to be processed with OSSL_CMP_get1_rootCaKeyUpdate(), that is expected to verify the 'newWithOld' certificate. A typo in the certificate chain building code led to adding an incorrect certificate ('newWithOld' instead of 'oldRoot') to the certificate chain, rendering the certificate verification process ineffectual (only the issuer name and the algorithm OIDs were verified by other parts of the verification code). An attacker who already has credentials that satisfy the CMP message protection checks can generate a new key pair and use a crafted self-signed certificate in its 'id-it-rootCaKeyUpdate' CMP messages which affected CMP clients would accept as a new trust anchor. Significant preconditions for the attack (having valid RA-level credentials) are the reason the issue was assigned Low severity. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-42769 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1opensslopenssl View
2opensslopenssl View
3opensslopenssl View
4opensslopenssl View
Total affected vendors: 1|Products: 4

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
5.3CVSS V31MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NNVD
5.3CVSS 3.x—CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NMicrosoft MSRC

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

9 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
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Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
reference

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reference

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reference

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reference

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reference

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Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-42769 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-2026-42769 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsLow
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

5.3 / 10
Attack VectorNetworkComplexityHighPrivilegesLowUser Interact.NoneConfidentialityHighIntegrityNoneAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredLow privileges
User InteractionNone required
Confidentiality (Gizlilik)High
Integrity (Bütünlük)None
Availability (Erişilebilirlik)None

Yama doğrulandı

9 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

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Weakness Type (CWE & CAPEC)

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