CVE-2026-55233 Details
Description
OpenResty is a high performance web platform. From 1.29.2.1 to before 1.29.2.5, an out-of-bounds write vulnerability exists in the upstream PROXY protocol v2 implementation. When OpenResty is configured to send PROXY protocol version 2 headers to upstream servers, constructing the header in the stream proxy protocol v2 patch can write beyond the bounds of the allocated buffer, causing the worker process to crash and resulting in a denial of service. Only configurations that explicitly enable PROXY protocol v2 for upstream connections are impacted. This issue is fixed in version 1.29.2.5.
A buffer overflow vulnerability has been identified in OpenResty versions 1.27.1.1 prior to 1.29.2.5. This vulnerability occurs in the upstream PROXY protocol version 2 implementation, where the header construction can write beyond the allocated buffer limits. This flaw leads to a crash of the worker process, causing a denial-of-service condition. The issue only affects configurations that explicitly enable PROXY protocol v2 for upstream connections, as the default is v1, which is not vulnerable.
Users should upgrade to OpenResty version 1.29.2.5 or later. For those unable to upgrade immediately, the upstream PROXY protocol version can be switched from v2 back to v1 in the configuration.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 13, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/openresty/openresty/commit/5c56ad2958a2dad8b2cc99f4987b8642cbc647d1 | [email protected] | Patch |
| https://github.com/openresty/openresty/security/advisories/GHSA-wx83-v28q-68gx | [email protected] | MitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-787 | Out-of-bounds Write | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openresty openresty | >= 1.29.2.1, < 1.29.2.5 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 14, 2026 | Initial Analysis | [email protected] |
| Jul 13, 2026 | CVE Modified | CISA-ADP |
| Jul 10, 2026 | New CVE Received | [email protected] |