CVE-2026-89407 (GCVE-0-2026-89407)

Vulnerability from cvelistv5 – Published: 2026-09-22 14:53 – Updated: 2026-09-22 15:52
VLAI
Title
jackson-core: quadratic backtracking in NumberInput.PATTERN_FLOAT via looksLikeValidNumber() enables ReDoS
Summary
NumberInput.looksLikeValidNumber() in FasterXML jackson-core pre-validates "stringified numbers" with two regular expressions: PATTERN_FLOAT ([+-]?[0-9]*[\.]?[0-9]+([eE][+-]?[0-9]+)?), present since 2.17.0, and PATTERN_FLOAT_TRAILING_DOT, added in 2.17.2. PATTERN_FLOAT places adjacent quantifiers over the same character class -- an optional [0-9]* run, an optional dot, then a required [0-9]+ run -- so input that ultimately fails to match forces Java's backtracking engine to retry every possible split point of the digit run.  Matching cost therefore grows with the square of the input length.  An attacker who can supply JSON that an application deserializes into a numeric target type reaches this method through jackson-databind's default String-to-number coercion (StdDeserializer and NumberDeserializers for BigDecimal, BigInteger, Double and Float).  Because StreamReadConstraints.maxStringLength defaults to 20,000,000 characters, no constraint bounds the input before it reaches the regex.  Testing by the reporter confirmed O(n^2) growth across five consecutive input-size doublings, with a single 160,000-character string consuming roughly 74 seconds in one call; a small number of concurrent requests of ordinary body size can therefore exhaust a server's request-handling thread pool.  The affected method does not exist before 2.17.0, so 2.16.x and earlier releases are not affected.  The fix replaces both regular expressions with a hand-rolled single-pass scan.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-22 15:52 UTC
CWE
  • CWE-1333 - Inefficient Regular Expression Complexity
  • CWE-400 - Uncontrolled Resource Consumption
Assigner
References
Impacted products
Vendor Product Version CPE status
FasterXML jackson-core Affected: 2.17.0 , ≤ 2.18.10 (maven)
Affected: 2.19.0 , ≤ 2.21.6 (maven)
Affected: 2.22.0 , ≤ 2.22.2 (maven)
guessed Create a notification for this product.
FasterXML jackson-core Affected: 3.0.0 , ≤ 3.1.6 (maven)
Affected: 3.2.0 , ≤ 3.2.1 (maven)
guessed Create a notification for this product.
Credits
manqingzhou
Show details on NVD website
To clipboard 

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                  "value": "\u003cp\u003eNumberInput.looksLikeValidNumber() in FasterXML jackson-core pre-validates \"stringified numbers\" with two regular expressions: PATTERN_FLOAT ([+-]?[0-9]*[\\.]?[0-9]+([eE][+-]?[0-9]+)?), present since 2.17.0, and PATTERN_FLOAT_TRAILING_DOT, added in 2.17.2. PATTERN_FLOAT places adjacent quantifiers over the same character class -- an optional [0-9]* run, an optional dot, then a required [0-9]+ run -- so input that ultimately fails to match forces Java\u0027s backtracking engine to retry every possible split point of the digit run.\u0026nbsp;\u003c/p\u003e\u003cp\u003eMatching cost therefore grows with the square of the input length.\u0026nbsp;\u003c/p\u003e\u003cp\u003eAn attacker who can supply JSON that an application deserializes into a numeric target type reaches this method through jackson-databind\u0027s default String-to-number coercion (StdDeserializer and NumberDeserializers for BigDecimal, BigInteger, Double and Float).\u0026nbsp;\u003c/p\u003e\u003cp\u003eBecause StreamReadConstraints.maxStringLength defaults to 20,000,000 characters, no constraint bounds the input before it reaches the regex.\u0026nbsp;\u003c/p\u003e\u003cp\u003eTesting by the reporter confirmed O(n^2) growth across five consecutive input-size doublings, with a single 160,000-character string consuming roughly 74 seconds in one call; a small number of concurrent requests of ordinary body size can therefore exhaust a server\u0027s request-handling thread pool.\u0026nbsp;\u003c/p\u003e\u003cp\u003eThe affected method does not exist before 2.17.0, so 2.16.x and earlier releases are not affected.\u0026nbsp;\u003c/p\u003e\u003cp\u003eThe fix replaces both regular expressions with a hand-rolled single-pass scan.\u003c/p\u003e"
                }
              ],
              "value": "NumberInput.looksLikeValidNumber() in FasterXML jackson-core pre-validates \"stringified numbers\" with two regular expressions: PATTERN_FLOAT ([+-]?[0-9]*[\\.]?[0-9]+([eE][+-]?[0-9]+)?), present since 2.17.0, and PATTERN_FLOAT_TRAILING_DOT, added in 2.17.2. PATTERN_FLOAT places adjacent quantifiers over the same character class -- an optional [0-9]* run, an optional dot, then a required [0-9]+ run -- so input that ultimately fails to match forces Java\u0027s backtracking engine to retry every possible split point of the digit run.\u00a0\n\n\n\nMatching cost therefore grows with the square of the input length.\u00a0\n\n\n\nAn attacker who can supply JSON that an application deserializes into a numeric target type reaches this method through jackson-databind\u0027s default String-to-number coercion (StdDeserializer and NumberDeserializers for BigDecimal, BigInteger, Double and Float).\u00a0\n\n\n\nBecause StreamReadConstraints.maxStringLength defaults to 20,000,000 characters, no constraint bounds the input before it reaches the regex.\u00a0\n\n\n\nTesting by the reporter confirmed O(n^2) growth across five consecutive input-size doublings, with a single 160,000-character string consuming roughly 74 seconds in one call; a small number of concurrent requests of ordinary body size can therefore exhaust a server\u0027s request-handling thread pool.\u00a0\n\n\n\nThe affected method does not exist before 2.17.0, so 2.16.x and earlier releases are not affected.\u00a0\n\n\n\nThe fix replaces both regular expressions with a hand-rolled single-pass scan."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-1333",
                  "description": "CWE-1333 Inefficient Regular Expression Complexity",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            },
            {
              "descriptions": [
                {
                  "cweId": "CWE-400",
                  "description": "CWE-400 Uncontrolled Resource Consumption",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-09-22T14:53:20.999Z",
            "orgId": "36c7be3b-2937-45df-85ea-ca7133ea542c",
            "shortName": "HeroDevs"
          },
          "references": [
            {
              "name": "GHSA-p6pp-m3f8-5c89",
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://github.com/FasterXML/jackson-core/security/advisories/GHSA-p6pp-m3f8-5c89"
            },
            {
              "name": "FasterXML/jackson-core#1649",
              "tags": [
                "issue-tracking"
              ],
              "url": "https://github.com/FasterXML/jackson-core/issues/1649"
            },
            {
              "name": "FasterXML/jackson-core#1650",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/FasterXML/jackson-core/pull/1650"
            },
            {
              "name": "FasterXML/jackson-core#1701 (2.18 backport)",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/FasterXML/jackson-core/pull/1701"
            }
          ],
          "solutions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eUpgrade to com.fasterxml.jackson.core:jackson-core 2.18.11, 2.21.7 or 2.22.3, or to tools.jackson.core:jackson-core 3.1.7 or 3.2.2. The 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; consumers of those lines must move forward to a maintained release.\u003c/p\u003e"
                }
              ],
              "value": "Upgrade to com.fasterxml.jackson.core:jackson-core 2.18.11, 2.21.7 or 2.22.3, or to tools.jackson.core:jackson-core 3.1.7 or 3.2.2. The 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; consumers of those lines must move forward to a maintained release."
            }
          ],
          "title": "jackson-core: quadratic backtracking in NumberInput.PATTERN_FLOAT via looksLikeValidNumber() enables ReDoS",
          "workarounds": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eUntil upgrading, lower StreamReadConstraints.maxStringLength well below its default of 20,000,000 characters so that oversized string tokens are rejected before number coercion, and apply wall-clock timeouts to parse and coercion operations. Because matching cost is quadratic in token length, a tight length bound substantially reduces worst-case cost. These are mitigations, not a complete fix.\u003c/p\u003e"
                }
              ],
              "value": "Until upgrading, lower StreamReadConstraints.maxStringLength well below its default of 20,000,000 characters so that oversized string tokens are rejected before number coercion, and apply wall-clock timeouts to parse and coercion operations. Because matching cost is quadratic in token length, a tight length bound substantially reduces worst-case cost. These are mitigations, not a complete fix."
            }
          ]
        }
      },
      "cveMetadata": {
        "assignerOrgId": "36c7be3b-2937-45df-85ea-ca7133ea542c",
        "assignerShortName": "HeroDevs",
        "cveId": "CVE-2026-89407",
        "datePublished": "2026-09-22T14:53:20.999Z",
        "dateReserved": "2026-09-11T16:07:58.141Z",
        "dateUpdated": "2026-09-22T15:52:44.881Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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