Description
The 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.
Published: 2026-10-01
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service
Action: Immediate Patch
AI Analysis

Impact

The CBOR parser in FasterXML jackson-dataformats-binary fails to enforce the StreamReadConstraints.maxNameLength limit when decoding JSON object property names. This omission allows an attacker to embed a property name of arbitrary length, causing the parser to buffer the entire name in memory before returning it. The result is a memory exhaustion scenario that leads to a denial of service, with no privilege escalation required beyond the ability to supply CBOR data to a parsing endpoint.

Affected Systems

Vendors impacted are FasterXML, specifically the jackson-dataformats-binary library. The issue exists in all versions before the fixed releases, including 2.16.0 through any 2.x lines that are not among the patched 2.18.10, 2.21.6, 2.22.2, 3.1.6, or 3.2.2, as well as the unmaintained 2.16.x, 2.17.x, 2.19.x, 2.20.x and 3.0.x branches. Systems that integrate these libraries and expose CBOR parsing to external input are at risk.

Risk and Exploitability

The vulnerability has a CVSS score of 7.5, indicating high severity, but its EPSS score is not available and it is not listed in the CISA KEV catalog. An attacker only needs to send a CBOR document containing a very large property name to a vulnerable parsing endpoint; no elevated privileges or additional prerequisites are required. Because the default maxDocumentLength is disabled, the attacker’s upload capacity and the JVM heap size are the only practical limits, making exploitation likely in environments where input size cannot be bounded.

Generated by OpenCVE AI on October 1, 2026 at 18:52 UTC.

Remediation

Vendor Solution

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.

Vendor Workaround

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.

OpenCVE Recommended Actions

  • Upgrade FasterXML jackson-dataformats-binary to one of the fixed releases: 2.18.10, 2.21.6, 2.22.2, 3.1.6, or 3.2.2. The older 2.16.x, 2.17.x, 2.19.x, 2.20.x, and 3.0.x lines are unpatched and no longer maintained upstream.
  • If an upgrade is infeasible, configure CBORFactory with an explicit StreamReadConstraints.maxDocumentLength and enforce a tight bound on request body size, ensuring that no single CBOR document can exceed the available heap space.
  • Apply a JVM heap size limit and, if possible, reject or truncate untrusted CBOR input before passing it to the parser to prevent large property names from exhausting memory.

Generated by OpenCVE AI on October 1, 2026 at 18:52 UTC.

Tracking

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Advisories

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History

Thu, 01 Oct 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 01 Oct 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Fasterxml
Fasterxml jackson-dataformats-binary
Vendors & Products Fasterxml
Fasterxml jackson-dataformats-binary

Thu, 01 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
Description The 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.
Title jackson-dataformats-binary: CBOR parser does not enforce StreamReadConstraints.maxNameLength, enabling memory-exhaustion denial of service
Weaknesses CWE-400
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Fasterxml Jackson-dataformats-binary
cve-icon MITRE

Status: PUBLISHED

Assigner: HeroDevs

Published:

Updated: 2026-10-01T18:16:39.815Z

Reserved: 2026-07-30T15:20:37.473Z

Link: CVE-2026-68495

cve-icon Vulnrichment

Updated: 2026-10-01T18:16:34.870Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-01T18:17:27.167

Modified: 2026-10-02T18:44:11.270

Link: CVE-2026-68495

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T19:00:16Z

Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption

  • CWE-770

    Allocation of Resources Without Limits or Throttling