jackson-core: Delayed maxNameLength enforcement for char-backed input (ReaderBasedJsonParser) allows memory-exhaustion denial of service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68498
StatePUBLISHED
AssignerHeroDevs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-16 22:17:25 UTC
Updated2026-10-16 22:17:25 UTC
DescriptionStreamReadConstraints.maxNameLength (default 50,000 characters) is intended to bound how much memory a single JSON Object property name can consume while being parsed, independently of the much larger maxStringLength (default 100,000,000 characters) that bounds ordinary string values. For parsers built over character input — Reader, String or char[] sources, all served by ReaderBasedJsonParser — that bound is not applied while the name is being accumulated. The code path instead re-uses the string-value length check, which is roughly 2000x larger by default. In the character-input slow path, ReaderBasedJsonParser._parseName2() accumulates the name into the TextBuffer and, when a segment fills, calls TextBuffer.finishCurrentSegment(), which validates only maxStringLength. The correct check, StreamReadConstraints.validateNameLength(int), is reached afterwards in CharsToNameCanonicalizer.findSymbol(), once the entire name has been scanned to its closing quote. By that point the full name — up to maxStringLength characters — has already been buffered in memory. A remote attacker who can have a single sufficiently long JSON Object property name parsed through this path can force allocation on the order of 100,000,000 characters (approximately 200 MB, with segment bookkeeping pushing real peak usage higher) before any StreamConstraintsException is thrown, instead of the approximately 50,000-character (about 100 KB) bound the API promises. Repeating this across concurrent requests can exhaust the heap and crash the process. No authentication or user interaction is required. Because StreamReadConstraints.maxDocumentLength is disabled by default (-1), nothing else bounds the token first, so the issue is exploitable under default configuration. Byte-input parsers are not affected: UTF8StreamJsonParser, UTF8DataInputJsonParser and the non-blocking (async) parsers re-validate maxNameLength on every growth of the name-decode buffer via ParserBase._growNameDecodeBuffer(), rejecting an oversized name after allocating only tens of kilobytes. Applications are exposed when untrusted JSON is parsed from a String, Reader or char[] — for example an HTTP request body already read into a String — rather than from raw UTF-8 bytes. This issue affects com.fasterxml.jackson.core:jackson-core from 2.16.0 and tools.jackson.core:jackson-core from 3.0.0. Releases before 2.16.0 are not affected, because StreamReadConstraints.maxNameLength was first introduced in jackson-core 2.16.0.

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

Problem Types: CWE-400 | 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-core affected 2.16.0 2.18.10 maven Not specified
CNA FasterXML Jackson-core unaffected 2.18.10 maven Not specified
CNA FasterXML Jackson-core affected 2.19.0 2.21.6 maven Not specified
CNA FasterXML Jackson-core unaffected 2.21.6 maven Not specified
CNA FasterXML Jackson-core affected 2.22.0 2.22.2 maven Not specified
CNA FasterXML Jackson-core unaffected 2.22.2 maven Not specified
CNA FasterXML Jackson-core affected 3.0.0 3.1.6 maven Not specified
CNA FasterXML Jackson-core unaffected 3.1.6 maven Not specified
CNA FasterXML Jackson-core affected 3.2.0 3.2.2 maven Not specified
CNA FasterXML Jackson-core unaffected 3.2.2 maven Not specified

References

ReferenceSourceLinkTags
github.com/FasterXML/jackson-core/blob/3.x/release-notes/VERSION 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
github.com/FasterXML/jackson-core/blob/2.x/release-notes/VERSION-2.x 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
github.com/FasterXML/jackson-core/security/advisories/GHSA-649p-m576-vr99 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
github.com/FasterXML/jackson-core/commit/2cd206de1163e3fcff7bdaca425274f... 36c7be3b-2937-45df-85ea-ca7133ea542c github.com
github.com/FasterXML/jackson-core/pull/1643 36c7be3b-2937-45df-85ea-ca7133ea542c 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)

CNA: tinyb0y (en)

CNA: cowtowncoder (Tatu Saloranta) (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-07-29T01:52:00.000ZFix merged upstream via FasterXML/jackson-core#1643
CNA2026-08-14T00:00:00.000ZFix released in jackson-core 2.21.6, 3.1.6 and 3.2.2
CNA2026-08-15T00:00:00.000ZFix released in jackson-core 2.18.10
CNA2026-08-16T00:00:00.000ZFix released in jackson-core 2.22.2
CNA2026-09-11T00:00:00.000ZGHSA-649p-m576-vr99 published by the maintainer in FasterXML/jackson-core

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