# CVE-2026-91769: TLS Hostname Verification Falls Back to CN After SAN Mismatch

> PHP's OpenSSL stream incorrectly accepts certificates with mismatched SANs if the CN matches, allowing attackers to bypass TLS hostname verification and impersonate servers.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Sep 2026
- **Updated:** 4 Oct 2026
- **Also known as:** AZL-104907, BELL-CVE-2026-91769, BIT-libphp-2026-91769, BIT-php-2026-91769, BIT-php-min-2026-91769, CLEANSTART-2026-AU05968, DEBIAN-CVE-2026-91769, ECHO-3821-500d-53fc, MINI-4vv6-9fjp-434v, MINI-85pc-pgq7-m36p, MINI-c2gp-c4g8-q3q6, MINI-m93h-7fwq-2x29, MINI-mrvc-p9cx-g3vf, MINI-mvqw-c8xr-4v3r, MINI-mw2c-77wc-2v6q, MINI-mx5c-7532-vfcj, UBUNTU-CVE-2026-91769

## What is CVE-2026-91769?

CVE-2026-91769 is a medium-severity vulnerability in Php Php, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-297 (Improper Validation of Certificate with Host Mismatch)

## Which versions are affected by CVE-2026-91769?

3 open source packages ship an affected version, including libphp, php and php-min. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libphp` | Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |
| `php` | Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |
| `php-min` | Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |

Products: Php Php.

## How do I fix CVE-2026-91769?

Upgrade libphp to a fixed version for your release line: 8.2.34, 8.3.35, 8.4.26 or 8.5.11.

## Is CVE-2026-91769 being exploited?

There is no known exploitation of CVE-2026-91769 in the wild and no public exploit code.

## Other vulnerabilities in Php Php

- [CVE-2012-2688](https://insights.sbomify.com/CVE-2012-2688/): Integer overflow in n/a (critical 10.0)
- [CVE-2012-2376](https://insights.sbomify.com/CVE-2012-2376/): Memory corruption in n/a (critical 10.0)
- [CVE-2011-3268](https://insights.sbomify.com/CVE-2011-3268/): Memory corruption in n/a (critical 10.0)
- [CVE-2009-4143](https://insights.sbomify.com/CVE-2009-4143/): Other in n/a (critical 10.0)
- [CVE-2008-5557](https://insights.sbomify.com/CVE-2008-5557/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91769 and fix it if it is affected.

What it is: CVE-2026-91769 is a medium-severity vulnerability in Php Php, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-91769 in the wild and no public exploit code.

Affected packages and fixed versions:
- libphp (Bitnami): affected from 8.2.0; fixed in 8.2.34, 8.3.35, 8.4.26, 8.5.11
- php (Bitnami): affected from 8.2.0; fixed in 8.2.34, 8.3.35, 8.4.26, 8.5.11
- php-min (Bitnami): affected from 8.2.0; fixed in 8.2.34, 8.3.35, 8.4.26, 8.5.11

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-91769/ (Markdown: https://insights.sbomify.com/CVE-2026-91769/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91769
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91769
- OSV: https://osv.dev/vulnerability/CVE-2026-91769

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91769/
Summaries are generated and may contain mistakes; the official description above is the record.