{"id":"CVE-2023-32731","aliases":["GHSA-cfgp-2977-2fmm","PYSEC-2026-1427"],"title":"Connection confusion in gRPC","summary":"Connection confusion in gRPC","severity":"high","cvss":7.4,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H","vendor":"grpc","product":"io.grpc:grpc-protobuf","ecosystem":"maven","affected":["io.grpc:grpc-protobuf >= 1.53.0, < 1.53.1","grpcio >= 1.53.0, < 1.53.1","grpc >= 1.53.0, < 1.53.1","grpcio >= 1.54.0, < 1.54.2","grpc >= 1.54.0, < 1.54.2","io.grpc:grpc-protobuf >= 1.54.0, < 1.54.2"],"patched":["io.grpc:grpc-protobuf 1.53.1","grpcio 1.53.1","grpc 1.53.1","grpcio 1.54.2","grpc 1.54.2","io.grpc:grpc-protobuf 1.54.2"],"published":"2023-07-05","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:49:57.873321723Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-cfgp-2977-2fmm","references":[{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-32731"},{"url":"https://github.com/grpc/grpc/issues/33463"},{"url":"https://github.com/grpc/grpc/pull/32309"},{"url":"https://github.com/grpc/grpc/pull/33005"},{"url":"https://github.com/grpc/grpc/commit/29d8beee0ac2555773b2a2dda5601c74a95d6c10"},{"url":"https://github.com/grpc/grpc/commit/65a2a895afaf1d2072447b9baf246374b182a946"},{"url":"https://github.com/grpc/grpc/releases/tag/v1.53.1"},{"url":"https://github.com/grpc/grpc/releases/tag/v1.54.2"},{"url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/grpc/CVE-2023-32731.yml"}],"tags":["osv","maven"],"epss":0.00502,"epssPercentile":0.42033,"ingestedAt":"2026-07-08T18:25:48.357Z","slug":"CVE-2023-32731","body":"## Overview\n\nWhen gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration.\n\n## Affected packages\n\n- `io.grpc:grpc-protobuf >= 1.53.0, < 1.53.1`\n- `grpcio >= 1.53.0, < 1.53.1`\n- `grpc >= 1.53.0, < 1.53.1`\n- `grpcio >= 1.54.0, < 1.54.2`\n- `grpc >= 1.54.0, < 1.54.2`\n- `io.grpc:grpc-protobuf >= 1.54.0, < 1.54.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `io.grpc:grpc-protobuf 1.53.1`\n- `grpcio 1.53.1`\n- `grpc 1.53.1`\n- `grpcio 1.54.2`\n- `grpc 1.54.2`\n- `io.grpc:grpc-protobuf 1.54.2`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":40.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}