CVE-2026-55233
OpenResty: Buffer overflow when writing PROXY protocol v2 header to upstream
CVSS Score
7.5
EPSS Score
0.3%
EPSS Percentile
26th
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.
| CWE | CWE-787 |
| Vendor | openresty |
| Product | openresty |
| Published | Jul 10, 2026 |
| Last Updated | Jul 13, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
openresty / openresty
>= 1.29.2.1, < 1.29.2.5