EUVD-2026-66958
HTTP Request/Response Smuggling (CWE-444)
2026-08-26
GHSA-3g86-xcpq-wppj
GHSA-3g86-xcpq-wppj
7.0
CVSS 4.0 · Vendor
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Vendor (CNA)
PRIMARY
7.0
HIGH
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today
AI
7.5
HIGH
Network-reachable gateway needs no auth; AC:H reflects HTTP smuggling timing complexity; scope changed because cross-user response leakage affects other clients' confidentiality.
3.1 AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:L/SA:N
Primary rating from Vendor (CNA).
CVSS VectorVendor
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X
Lifecycle Timeline
2
CVSS changed
Aug 27, 2026 - 10:22 NVD
7.0 (HIGH)
Analysis Generated
Aug 26, 2026 - 16:22 vuln.today
Description PRE-NVD
Disclosed via oss-security. NVD scoring and full description are pending.
Articles & Coverage 1
AnalysisAI
Response poisoning in Apache APISIX 2.12.0 through 3.17.0 enables remote attackers to manipulate the gateway's serverless plugin routes so that victims receive attacker-chosen content or other authenticated users' API responses. The root cause is inconsistent HTTP request boundary interpretation - the defining characteristic of HTTP Request/Response Smuggling - applied within APISIX's serverless plugin execution pipeline. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Access
Send crafted HTTP requests to serverless-plugin route
Delivery
Exploit inconsistent request boundary parsing in gateway
Exploit
Desynchronize response-to-connection mapping
Execution
Victim request served attacker-chosen or another user's response
Impact
Sensitive API response data disclosed or integrity violated
Access
Send crafted HTTP requests to serverless-plugin route
Delivery
Exploit inconsistent request boundary parsing in gateway
Exploit
Desynchronize response-to-connection mapping
Execution
Victim request served attacker-chosen or another user's response
Impact
Sensitive API response data disclosed or integrity violated
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the targeted Apache APISIX instance is running a version between 2.12.0 and 3.17.0 inclusive, and that at least one route is configured to use a serverless plugin (serverless-pre-function or serverless-post-function). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | No CVSS vector was supplied with this advisory, limiting quantitative scoring; independent metrics are assessed below. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A remote attacker sends a sequence of specially crafted HTTP requests to an Apache APISIX serverless-plugin route, exploiting ambiguous request boundary parsing to desynchronize the gateway's connection handling. A victim who subsequently sends a legitimate request over the same or a pipelined connection receives the attacker's injected response content - or another authenticated user's API response - potentially exposing session tokens, business data, or PII. … |
| Remediation | The primary and confirmed fix is upgrading Apache APISIX to version 3.18.0, which addresses the inconsistent HTTP request boundary handling in serverless plugin routes; upgrade procedures and release notes are available at https://apisix.apache.org. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-444 – HTTP Request/Response Smuggling
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External POC / Exploit Code
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