Heap-buffer-overflow in php_openssl_matches_wildcard_name on crafted server cert wildcard CN
CVSS score
6.5
EPSS probability
%0.2
Risk score
0.0
Published
16 d ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-91767 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed to memchr() when a TLS server certificate presents a wildcard name whose literal characters are together longer than the hostname being verified. A malicious server presenting such a certificate makes the PHP client read up to SIZE_MAX bytes past the end of a heap allocation. The path is reachable from any default client stream, because verify_peer_name is enabled by default.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-91767 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 |
|---|---|---|---|---|
| 6.5 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | CVE CNA |
| 6.5 | CVSS V31 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/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-2026-91767 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-2026-91767 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
6.5 / 10Vulnerability Scoring Details
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NYama durumu bilinmiyor
Weakness Type (CWE & CAPEC)
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Get this vulnerability through the API
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curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-91767"