CVE-2026-91767
Heap-buffer-overflow in php_openssl_matches_wildcard_name on crafted server cert wildcard CN
Description
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.
INFO
Published Date :
Sept. 25, 2026, 9:17 p.m.
Last Modified :
Sept. 25, 2026, 9:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | dd77f84a-d19a-4638-8c3d-a322d820ed2b | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update PHP to the latest secure version.
- Verify OpenSSL certificate validation logic.
- Apply vendor patches if available.
- Limit wildcard certificate usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-91767.
| URL | Resource |
|---|---|
| https://github.com/php/php-src/security/advisories/GHSA-xr7j-rvgx-xq5p |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-91767 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.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-91767 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-91767 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Sep. 25, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-122 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/91xxx/CVE-2026-91767.json">CVE-2026-91767</a> Added Reference https://github.com/php/php-src/security/advisories/GHSA-xr7j-rvgx-xq5p