Vulnerability details

CVE-2026-55233

openresty openresty

OpenResty: Buffer overflow when writing PROXY protocol v2 header to upstream

CVSS 3.1

7.5High

Official 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.

CVSS scores

Score	Version	Source	Vector
7.5High	3.1	CVEProject cvelistV5 (CNA) (GitHub_M)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

Affected products

Vendor	Product	Versions	Source
openresty	openresty	>= 1.29.2.1, < 1.29.2.5	CVEProject cvelistV5 (CNA)

References and advisories

https://github.com/openresty/openresty/security/advisories/GHSA-wx83-v28q-68gx x_refsource_CONFIRM
https://github.com/openresty/openresty/commit/5c56ad2958a2dad8b2cc99f4987b8642cbc647d1 x_refsource_MISC

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Details

Published: 2026-07-10
Last updated: 2026-07-13
State: Published
Assigner (CNA): GitHub_M

Exploit prediction (EPSS)

0.48%

Probability of exploitation in 30 days

42.2%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Partial

Weaknesses (CWE)

CWE-787
Out-of-bounds Write