TLS Hostname Verification Falls Back to CN After SAN Mismatch
CVSS score
4.3
EPSS probability
%0.1
Risk score
0.0
Published
16 d ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-91769 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-91769 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | PHP Group | PHP | View |
RED HAT CSAF/VEX: Product Impact Check
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.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 4.3 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | CVE CNA |
| 4.3 | CVSS V31 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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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-2026-91769 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-2026-91769 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
4.3 / 10Vulnerability Scoring Details
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NYama durumu bilinmiyor
Weakness Type (CWE & CAPEC)
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Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-91769"