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CVE-2026-26308

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, the Envoy RBAC (Role-Based Access Control) filter contains a logic vulnerability in how it validates HTTP headers when multiple values are present for the same header name. Instead of validating each header value individually, Envoy concatenates all values into a single comma-separated string. This behavior allows attackers to bypass RBAC policies—specifically "Deny" rules—by sending duplicate he
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:0924df6d8a6d1cd90d583f9143dd20bcb1135245762e6fbd230b6118f3239894
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0

Affected products and versions

1 source assertion
{"product":"envoy","vendor":"envoyproxy","versions":[{"status":"affected","version":">= 1.37.0, < 1.37.1"},{"status":"affected","version":">= 1.36.0, < 1.36.5"},{"status":"affected","version":">= 1.35.0, < 1.35.9"},{"status":"affected","version":"< 1.34.13"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:9d3fb89c470897de6ca53fe81c9eb7d3d597ccc4772192ab8bf60ad40d09583e · sha256:57c1d4db82f62e9d… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion
{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:9d3fb89c470897de6ca53fe81c9eb7d3d597ccc4772192ab8bf60ad40d09583e · sha256:57c1d4db82f62e9d… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

1 source assertion
{"cweId":"CWE-863","description":"CWE-863: Incorrect Authorization","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:9d3fb89c470897de6ca53fe81c9eb7d3d597ccc4772192ab8bf60ad40d09583e · sha256:57c1d4db82f62e9d… · /containers/cna/problemTypes/0/descriptions/0

Source references

2 source assertions
{"name":"https://github.com/envoyproxy/envoy/commit/b6ba0b2294b98484fb0ed8556897d1073cc27867","tags":["x_refsource_MISC"],"url":"https://github.com/envoyproxy/envoy/commit/b6ba0b2294b98484fb0ed8556897d1073cc27867"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:9d3fb89c470897de6ca53fe81c9eb7d3d597ccc4772192ab8bf60ad40d09583e · sha256:57c1d4db82f62e9d… · /containers/cna/references/1
{"name":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-ghc4-35x6-crw5","tags":["x_refsource_CONFIRM"],"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-ghc4-35x6-crw5"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:9d3fb89c470897de6ca53fe81c9eb7d3d597ccc4772192ab8bf60ad40d09583e · sha256:57c1d4db82f62e9d… · /containers/cna/references/0

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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