jackson-dataformats-binary: CBOR parser does not enforce StreamReadConstraints.maxNameLength, enabling memory-exhaustion denial of service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68495
StatePUBLISHED
AssignerHeroDevs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-01 18:17:27 UTC
Updated2026-10-02 18:44:11 UTC
DescriptionThe CBOR parser in FasterXML jackson-dataformats-binary never invokes StreamReadConstraints.validateNameLength() when decoding JSON object property names, so the maxNameLength limit is not enforced for this format. CBORParser._decodeLongerName() decodes a definite-length property name with no length check, and CBORParser._decodeChunkedName() delegates to the value-oriented _finishChunkedText() routine, which validates maxStringLength rather than maxNameLength. An attacker who can have a CBOR document parsed may therefore embed a single property name of unbounded length; the parser buffers the whole name in memory before returning it, whatever maxNameLength is configured to. Because StreamReadConstraints.maxDocumentLength is also disabled by default, nothing else bounds the name under default settings, so the only limits are the attacker's upload capacity and available heap, leading to memory exhaustion and denial of service. No privileges beyond the ability to submit data to a parsing endpoint are required, and exploitation needs only that the bytes reach CBORFactory parsing, directly or through an ObjectMapper configured with the CBOR module. jackson-core's own JSON parsers enforce maxNameLength incrementally during name decoding; this gap is specific to the binary formats. maxNameLength and validateNameLength were introduced in jackson-core 2.16.0, so releases before 2.16.0 do not contain the constraint that is left unenforced. This issue is tracked together with the Smile parser defect in the same vendor advisory, GHSA-3v8f-v6vx-fmrm, which covers both binary formats. The CBOR parser defect (jackson-dataformats-binary issue #725) is CVE-2026-68495; the Smile parser defect (issue #726) is assigned CVE-2026-68496.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 36c7be3b-2937-45df-85ea-ca7133ea542c

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.006660000 probability, percentile 0.500960000 (date 2026-10-05)

Problem Types: CWE-400 | CWE-770 | CWE-770 CWE-770 Allocation of Resources Without Limits or Throttling | CWE-400 CWE-400 Uncontrolled Resource Consumption

VersionSourceTypeScoreSeverityVector
3.136c7be3b-2937-45df-85ea-ca7133ea542cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FasterXML Jackson-dataformats-binary affected 2.16.0 2.18.9 maven Not specified
CNA FasterXML Jackson-dataformats-binary affected 2.19.0 2.21.5 maven Not specified
CNA FasterXML Jackson-dataformats-binary affected 2.22.0 2.22.1 maven Not specified
CNA FasterXML Jackson-dataformats-binary affected 3.0.0 3.1.5 maven Not specified
CNA FasterXML Jackson-dataformats-binary affected 3.2.0 3.2.1 maven Not specified

References

ReferenceSourceLinkTags
github.com/FasterXML/jackson-dataformats-binary/issues/725 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
www.cve.org/CVERecord 36c7be3b-2937-45df-85ea-ca7133ea542c www.cve.org
github.com/FasterXML/jackson-dataformats-binary/blob/2.18/release-notes/... 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: tinyb0y (en)

Additional Advisory Data

Solutions

CNA: Upgrade to com.fasterxml.jackson.dataformat:jackson-dataformat-cbor 2.18.10, 2.21.6 or 2.22.2, or to tools.jackson.dataformat:jackson-dataformat-cbor 3.1.6 or 3.2.2. The 2.16.x, 2.17.x, 2.19.x, 2.20.x and 3.0.x lines received no fix on their own branch and are no longer maintained upstream.

Workarounds

CNA: No StreamReadConstraints setting mitigates this: maxNameLength is the control that is not enforced, and maxDocumentLength is disabled by default (-1). Bound request body size ahead of the parser, set StreamReadConstraints.maxDocumentLength explicitly on the CBORFactory, and cap JVM heap so a single document cannot exhaust process memory. Avoid parsing untrusted CBOR input where these limits cannot be applied.

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