{"id":"CVE-2026-71884","revision":null,"records":[{"revision":"5ba376dccc3c46c1a2d18da8b028f053","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-71884","aliases":[],"title":"Packet CTR reports a full success length after the counter is exhausted","description":"In Bouncy Castle for Java LTS before 2.73.13, the native one-shot CTR packet cipher did not check that the requested input length fitted the counter space the IV left. In CTR mode the IV and the block counter share one 16-byte block, so an IV of 13 to 15 bytes leaves a counter of only 1 to 3 bytes, addressing 256, 65536 or 16777216 blocks respectively. Given a longer input the counter wrapped and the keystream repeated from the start of the same packet, and the call then returned the full input length as though every byte had been correctly transformed. Two segments of the message were therefore encrypted under the same keystream, so their plaintexts can be recovered from the ciphertext alone, without the key, while the caller saw neither an exception nor a short length to indicate it. The streaming implementation validates at init and again while processing, and the portable AESCTRPacketCipher rejects such a request with \"Counter in CTR/SIC mode out of range.\", but the native one-shot path has a single entry point and performed no counter-range validation there. It now preflights the IV-derived counter range and rejects an over-long request before any output is written, so the operation is failure-atomic and never reports success for bytes it did not correctly transform. A counter of four bytes or more cannot be exhausted by a Java int length and is unaffected, as is a full 16-byte IV, where the counter range is the caller's responsibility. Bouncy Castle for Java (bcprov) is not affected, as it ships no native implementations.","state":0,"publishedAt":"2026-10-09T09:30:50.624+00:00","modifiedAt":"2026-10-15T16:03:50.989+00:00","affected":[{"ecosystem":"https://www.bouncycastle.org/download/bouncy-castle-java-lts/","name":"bcprov-lts8on","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Legion of the Bouncy Castle Inc.\",\n                    \"product\": \"BC-LTS-JAVA\",\n                    \"platforms\": [\n                        \"x86\",\n                        \"x86-64\"\n                    ],\n                    \"collectionURL\": \"https://www.bouncycastle.org/download/bouncy-castle-java-lts/\",\n                    \"packageName\": \"bcprov-lts8on\",\n                    \"repo\": \"https://github.com/bcgit/bc-lts-java\",\n                    \"packageURL\": \"pkg:maven/org.bouncycastle/bcprov-lts8on\",\n                    \"modules\": [\n                        \"core\"\n                    ],\n                    \"programFiles\": [\n                        \"ctr_pc.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"2.73.4\",\n                            \"lessThan\": \"2.73.13\",\n                            \"versionType\": \"maven\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/U:Amber","score":8.2,"severity":"HIGH"}],"references":["https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9071884"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-71884","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-71884","identifiers":["CVE-2026-71884"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-09T15:04:17.9226009+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-09T15:04:17.9226009+00:00","lastSuccessAt":"2026-11-09T15:04:18.1621362+00:00","error":null,"lastVerifiedAt":"2026-11-09T15:04:18.1621395+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-24e6fde7b744113daefb8f6135035fb8a5c69c9617c9c0d40574a0376532ffd3-777857808926e2a726f3d34c96aa6f2fd3a523fc0c567e8eb45c32df9990ab78","complete":true,"records":421467,"lastAttemptAt":"2026-11-09T16:02:15.9126814+00:00","lastSuccessAt":"2026-11-09T16:02:15.8355527+00:00","error":null,"lastVerifiedAt":"2026-11-09T16:02:15.9126814+00:00","snapshotPublishedAt":"2026-11-09T15:23:15+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-1cda4ef84588402c81419af30caa5cf1","complete":false,"records":13655,"lastAttemptAt":"2026-11-09T15:16:31.927767+00:00","lastSuccessAt":"2026-11-09T15:16:31.919+00:00","error":"9 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-09T15:16:31.919+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13698,"expectedIdentifiers":13707,"failedIdentifiers":9},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T15:04:17.9226009+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T15:04:17.9226009+00:00","lastSuccessAt":"2026-11-09T15:04:18.1628494+00:00","error":null,"lastVerifiedAt":"2026-11-09T15:04:18.1628497+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-122e73413fbf41e4b6ede4e4f5660885","complete":true,"records":13667,"lastAttemptAt":"2026-11-09T15:04:19.7498555+00:00","lastSuccessAt":"2026-11-09T15:04:19.744+00:00","error":null,"lastVerifiedAt":"2026-11-09T15:04:19.744+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13707,"expectedIdentifiers":13707,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T15:04:17.5233893+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T15:04:17.5233893+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T16:02:16.0730731+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-09T16:02:16.0730731+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-c905fa1bd26c7b261e77cc7202a86dc766ff31c2b096b501f3bf44f561e34970","complete":true,"records":3063,"lastAttemptAt":"2026-11-09T15:04:17.8913143+00:00","lastSuccessAt":"2026-11-09T12:02:21.7931207+00:00","error":null,"lastVerifiedAt":"2026-11-09T15:04:17.8913143+00:00","snapshotPublishedAt":"2026-11-09T11:18:00+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-e88565d90b43c4a1bda916e33427c1b6f49f68cfbb010c54e1b5410320dbe0cf","complete":true,"records":231301,"lastAttemptAt":"2026-11-09T16:03:48.0777915+00:00","lastSuccessAt":"2026-11-09T16:04:18.2915457+00:00","error":null,"lastVerifiedAt":"2026-11-09T16:04:18.2915457+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}