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CVE-2026-55233

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

Published: Jul 10, 2026Updated: Jul 14, 2026 Sources: CVE List NVDCWE-787
7.5HIGH
NVD MITRE
EPSS Score
0.5%
Top 60.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-787

Affected Products

openresty
oss-projectaka openresty bundle, resty
openrestyOn-prem
OSS Libraries / web-framework

Exploitability

Official Patch Available
Workaround Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

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

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