One CBOR-parsing issue in jackson-dataformats-binary's CBOR module: an unbounded run of CBOR tags drives quadratic-time TagList growth (CPU/GC-exhaustion DoS, PoC-proven).
PoC executed against com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:2.18.2; present in current 2.x and 3.x (tools.jackson.dataformat.cbor) HEAD. Distinct from the Avro and Smile/Protobuf advisories for this repo.
Quadratic CPU/GC DoS from an unbounded chain of CBOR tags (PoC-proven). File: cbor/src/main/java/.../cbor/CBORParser.java (tag handling -> TagList).
CBOR permits a data item to be preceded by any number of semantic tags. The CBOR parser accumulates them in a TagList whose backing array grows by a fixed increment (+8), not by doubling, and re-scans/copies on each growth. An attacker sends a value preceded by a long run of tag bytes; the fixed-increment growth makes accumulating N tags O(N^2) in time (plus GC pressure), with no cap on the number of stacked tags.
PoC (executed, JDK 17): feeding a CBOR stream consisting of a long run of tag bytes (e.g. tag 0xC0+) before a trivial value forces quadratic CPU/GC; parse time grows super-linearly with the tag count, pinning a request thread with no configurable limit.
Impact. Algorithmic-complexity denial of service (CWE-407): a modest input of stacked tags consumes quadratic CPU/GC, pinning a request thread; concurrent requests exhaust the pool.
Fix. Grow TagList by doubling and/or cap the number of stacked tags (StreamReadConstraints-style).
"}],"value":"One CBOR-parsing issue in jackson-dataformats-binary's CBOR module: an unbounded run of CBOR tags drives quadratic-time TagList growth (CPU/GC-exhaustion DoS, PoC-proven).\n\n\n\nPoC executed against com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:2.18.2; present in current 2.x and 3.x (tools.jackson.dataformat.cbor) HEAD. Distinct from the Avro and Smile/Protobuf advisories for this repo.\n\n\n\nQuadratic CPU/GC DoS from an unbounded chain of CBOR tags (PoC-proven). File: cbor/src/main/java/.../cbor/CBORParser.java (tag handling -> TagList).\n\n\n\nCBOR permits a data item to be preceded by any number of semantic tags. The CBOR parser accumulates them in a TagList whose backing array grows by a fixed increment (+8), not by doubling, and re-scans/copies on each growth. An attacker sends a value preceded by a long run of tag bytes; the fixed-increment growth makes accumulating N tags O(N^2) in time (plus GC pressure), with no cap on the number of stacked tags.\n\n\n\nPoC (executed, JDK 17): feeding a CBOR stream consisting of a long run of tag bytes (e.g. tag 0xC0+) before a trivial value forces quadratic CPU/GC; parse time grows super-linearly with the tag count, pinning a request thread with no configurable limit.\n\n\n\nImpact. Algorithmic-complexity denial of service (CWE-407): a modest input of stacked tags consumes quadratic CPU/GC, pinning a request thread; concurrent requests exhaust the pool.\n\n\n\nFix. Grow TagList by doubling and/or cap the number of stacked tags (StreamReadConstraints-style)."}],"metrics":[{"format":"other","other":{"content":{"text":"MEDIUM"},"type":"severity"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-407","description":"CWE-407 Inefficient Algorithmic Complexity","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-04T16:14:05.664Z","orgId":"36c7be3b-2937-45df-85ea-ca7133ea542c","shortName":"HeroDevs"},"references":[{"name":"GHSA-cjg7-h3pr-p927","tags":["vendor-advisory"],"url":"https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-cjg7-h3pr-p927"}],"source":{"advisory":"GHSA-cjg7-h3pr-p927","discovery":"EXTERNAL"},"tags":["x_open-source"],"timeline":[{"lang":"en","time":"2026-10-22T21:30:00.000Z","value":"GHSA-cjg7-h3pr-p927 published in FasterXML/jackson-dataformats-binary"}],"title":"jackson-dataformat-cbor: quadratic-time TagList growth on unbounded stacked tags (CPU/GC DoS, PoC)","x_generator":{"engine":"Vulnogram 0.5.0"}}},"cveMetadata":{"assignerOrgId":"36c7be3b-2937-45df-85ea-ca7133ea542c","assignerShortName":"HeroDevs","cveId":"CVE-2026-106554","datePublished":"2026-11-04T16:14:05.664Z","dateReserved":"2026-10-06T20:27:12.839Z","dateUpdated":"2026-11-04T16:14:05.664Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-04 16:17:32","lastModifiedDate":"2026-11-04 16:17:32","problem_types":["CWE-407","CWE-407 CWE-407 Inefficient Algorithmic Complexity"],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"106554","Ordinal":"1","Title":"jackson-dataformat-cbor: quadratic-time TagList growth on unboun","CVE":"CVE-2026-106554","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"106554","Ordinal":"1","NoteData":"One CBOR-parsing issue in jackson-dataformats-binary's CBOR module: an unbounded run of CBOR tags drives quadratic-time TagList growth (CPU/GC-exhaustion DoS, PoC-proven).\n\n\n\nPoC executed against com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:2.18.2; present in current 2.x and 3.x (tools.jackson.dataformat.cbor) HEAD. Distinct from the Avro and Smile/Protobuf advisories for this repo.\n\n\n\nQuadratic CPU/GC DoS from an unbounded chain of CBOR tags (PoC-proven). File: cbor/src/main/java/.../cbor/CBORParser.java (tag handling -> TagList).\n\n\n\nCBOR permits a data item to be preceded by any number of semantic tags. The CBOR parser accumulates them in a TagList whose backing array grows by a fixed increment (+8), not by doubling, and re-scans/copies on each growth. An attacker sends a value preceded by a long run of tag bytes; the fixed-increment growth makes accumulating N tags O(N^2) in time (plus GC pressure), with no cap on the number of stacked tags.\n\n\n\nPoC (executed, JDK 17): feeding a CBOR stream consisting of a long run of tag bytes (e.g. tag 0xC0+) before a trivial value forces quadratic CPU/GC; parse time grows super-linearly with the tag count, pinning a request thread with no configurable limit.\n\n\n\nImpact. Algorithmic-complexity denial of service (CWE-407): a modest input of stacked tags consumes quadratic CPU/GC, pinning a request thread; concurrent requests exhaust the pool.\n\n\n\nFix. Grow TagList by doubling and/or cap the number of stacked tags (StreamReadConstraints-style).","Type":"Description","Title":"jackson-dataformat-cbor: quadratic-time TagList growth on unboun"}]}}}