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CVE-2026-68498— jackson-core: Delayed maxNameLength enforcement for char-backed input (ReaderBasedJsonParser) allows memory-exhaustion denial of service

Quick assessment

Affected
FasterXML jackson-core
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

（默认值为 50,000 个字符）旨在限制单个 JSON 对象属性名在解析过程中可消耗的内存量，其限制范围独立于用于限制普通字符串值的 （默认值为 100,000,000 个字符）。然而，对于基于字符输入构建的解析器（即输入源为 、 或 ，均由 提供服务），在属性名累积过程中并未应用该限制。相反，代码路径复用了字符串值的长度检查机制，而该机制的默认阈值约为属性名限制阈值的 2000 倍。 在基于字符输入的慢速路径中， 方法会将属性名累积到 中；当某个缓冲区段填满时，会调用 ，而该方法仅验证 。正确的检查逻辑 要等到

CVSS 7.5 · High

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-68498

Vulnerability Information
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Vulnerability Title
jackson-core: Delayed maxNameLength enforcement for char-backed input (ReaderBasedJsonParser) allows memory-exhaustion denial of service
Source: CVE Program / CVE List V5
Vulnerability Description
StreamReadConstraints.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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
FasterXML jackson-core 2.16.0 ~ 2.18.10 -
FasterXML jackson-core 3.0.0 ~ 3.1.6 -

II. Public POCs for CVE-2026-68498

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III. Intelligence Information for CVE-2026-68498

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Patches & Fixes for CVE-2026-68498 (1)

Vendor Advisories for CVE-2026-68498 (1)

Vendor Pages for CVE-2026-68498 (1)

IV. Related Vulnerabilities

Same product: jackson-core
Same vendor: FasterXML
Same weakness: CWE-400

V. Comments for CVE-2026-68498

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