Inefficient Algorithmic Complexity

Summary

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. Affected versions for "com.fasterxml.jackson.dataformat:jackson-dataformat-cbor"are from 2.15.0 prior to 2.18.12, 2.19.0 prior to 2.21.8, and 2.22.0 prior to 2.22.4. Fixed in 2.18.12, 2.21.8 and 2.22.4. Affected versions for "tools.jackson.dataformat:jackson-dataformat-cbor" are from 3.0.0 prior to 3.1.8, and 3.2.0 prior to 3.2.4. Fixed in 3.1.8 and 3.2.4. Fix. Grow TagList by doubling and/or cap the number of stacked tags (StreamReadConstraints-style).