FasterXML jackson-dataformat-cbor 2.x/3.x CBOR Parser CBORParser.java algorithmic complexity

Summaryinfo

A vulnerability was found in FasterXML jackson-dataformat-cbor 2.x/3.x. It has been rated as problematic. This vulnerability affects unknown code of the file cbor/src/main/java/cbor/CBORParser.java of the component CBOR Parser. This manipulation causes algorithmic complexity. This vulnerability is tracked as CVE-2026-106554. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic was found in FasterXML jackson-dataformat-cbor 2.x/3.x. Affected by this vulnerability is an unknown function of the file cbor/src/main/java/cbor/CBORParser.java of the component CBOR Parser. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. The CWE definition for the vulnerability is CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. As an impact it is known to affect availability. The summary by CVE is:

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).

The advisory is shared at github.com. This vulnerability is known as CVE-2026-106554 since 10/06/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Programming Language Software

Vendor

• FasterXML

Name

• jackson-dataformat-cbor

Version

• 2.x
• 3.x

License

• open-source

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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