CVE-2026-68494
Full vulnerability record from the local CVENow database.
Description
The fix released in jackson-core 2.18.6 and 2.21.1 for CVE-2026-18401 (GHSA-72hv-8253-57qq, number length constraint bypass in the non-blocking parser) is incomplete. This record covers the remaining bypass. The earlier fix wired validateIntegerLength() into a new _setIntLength() helper and invoked it wherever the integer portion of a number is decided: a terminator byte arrives, a '.' or 'e'/'E' is seen, or input ends inside a fully buffered value. It was not invoked on the attacker-relevant path where the parser runs out of input while still inside the MINOR_NUMBER_INTEGER_DIGITS minor state and returns NOT_AVAILABLE to the caller. As a result, an attacker who streams JSON to a non-blocking parser in many small chunks, without ever sending a terminator byte, keeps the parser inside MINOR_NUMBER_INTEGER_DIGITS indefinitely. _textBuffer.expandCurrentSegment() grows the accumulator on every chunk while validateIntegerLength() is never called. The accumulator is bounded only by maxStringLength (20 MiB by default) rather than by maxNumberLength (1000 by default), an amplification of roughly 20,000x over the documented limit. Because Java char values occupy two bytes, a single connection can be driven to approximately 40 MiB of heap before the validator finally fires when the value completes. The equivalent fraction-path code is correct: _finishFloatFraction() calls _setFractLength() before its NOT_AVAILABLE return. The missing call affects the integer-digit paths in _startPositiveNumber(), _startNegativeNumber() and _finishNumberIntegralPart() in NonBlockingUtf8JsonParserBase. Impact: reactive frameworks such as Spring WebFlux/Reactor, Quarkus, Helidon and Vert.x feed inbound HTTP or gRPC bytes to the async parser as they arrive, which is precisely the chunked-feed shape required. Operators who set StreamReadConstraints.maxNumberLength expecting it to cap memory per number value do not get that guarantee; memory accumulates per concurrent connection and attacker-controlled concurrency can exhaust the JVM heap. The synchronous parsers (UTF8StreamJsonParser, ReaderBasedJsonParser) and the async parser operating on complete input are not affected. Exploitation requires only the ability to stream data to a parsing endpoint; no privileges or user interaction are needed. This issue affects com.fasterxml.jackson.core:jackson-core from version 2.15.0 through 2.18.7, and from 2.19.0 through 2.21.3, and tools.jackson.core:jackson-core from 3.0.0 through 3.1.3. Versions prior to 2.15.0 are not affected, because StreamReadConstraints -- which defines the maxNumberLength setting -- was first introduced in jackson-core 2.15.0, so no such constraint exists to be bypassed in earlier releases. Note that GHSA-r7wm-3cxj-wff9 states the affected 2.x range without a lower bound. The 2.22.x and 3.2.x release lines are not affected: those branches were created after the fix commit landed on 2026-05-21 and therefore contain it from their initial releases (2.22.0, tagged 2026-06-03, and 3.2.0, tagged 2026-06-08).
View original CVE JSON
{
"id": "CVE-2026-68494",
"sourceIdentifier": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"published": "2026-08-04T15:16:41.443",
"lastModified": "2026-10-23T23:10:00.157",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "The fix released in jackson-core 2.18.6 and 2.21.1 for CVE-2026-18401 (GHSA-72hv-8253-57qq, number length constraint bypass in the non-blocking parser) is incomplete. This record covers the remaining bypass.\n\nThe earlier fix wired validateIntegerLength() into a new _setIntLength() helper and invoked it wherever the integer portion of a number is decided: a terminator byte arrives, a '.' or 'e'/'E' is seen, or input ends inside a fully buffered value. It was not invoked on the attacker-relevant path where the parser runs out of input while still inside the MINOR_NUMBER_INTEGER_DIGITS minor state and returns NOT_AVAILABLE to the caller.\n\nAs a result, an attacker who streams JSON to a non-blocking parser in many small chunks, without ever sending a terminator byte, keeps the parser inside MINOR_NUMBER_INTEGER_DIGITS indefinitely. _textBuffer.expandCurrentSegment() grows the accumulator on every chunk while validateIntegerLength() is never called. The accumulator is bounded only by maxStringLength (20 MiB by default) rather than by maxNumberLength (1000 by default), an amplification of roughly 20,000x over the documented limit. Because Java char values occupy two bytes, a single connection can be driven to approximately 40 MiB of heap before the validator finally fires when the value completes.\n\nThe equivalent fraction-path code is correct: _finishFloatFraction() calls _setFractLength() before its NOT_AVAILABLE return. The missing call affects the integer-digit paths in _startPositiveNumber(), _startNegativeNumber() and _finishNumberIntegralPart() in NonBlockingUtf8JsonParserBase.\n\nImpact: reactive frameworks such as Spring WebFlux/Reactor, Quarkus, Helidon and Vert.x feed inbound HTTP or gRPC bytes to the async parser as they arrive, which is precisely the chunked-feed shape required. Operators who set StreamReadConstraints.maxNumberLength expecting it to cap memory per number value do not get that guarantee; memory accumulates per concurrent connection and attacker-controlled concurrency can exhaust the JVM heap. The synchronous parsers (UTF8StreamJsonParser, ReaderBasedJsonParser) and the async parser operating on complete input are not affected.\n\nExploitation requires only the ability to stream data to a parsing endpoint; no privileges or user interaction are needed.\n\nThis issue affects com.fasterxml.jackson.core:jackson-core from version 2.15.0 through 2.18.7, and from 2.19.0 through 2.21.3, and tools.jackson.core:jackson-core from 3.0.0 through 3.1.3. Versions prior to 2.15.0 are not affected, because StreamReadConstraints -- which defines the maxNumberLength setting -- was first introduced in jackson-core 2.15.0, so no such constraint exists to be bypassed in earlier releases. Note that GHSA-r7wm-3cxj-wff9 states the affected 2.x range without a lower bound. The 2.22.x and 3.2.x release lines are not affected: those branches were created after the fix commit landed on 2026-05-21 and therefore contain it from their initial releases (2.22.0, tagged 2026-06-03, and 3.2.0, tagged 2026-06-08)."
},
{
"lang": "es",
"value": "La corrección lanzada en jackson-core 2.18.6 y 2.21.1 para CVE-2026-18401 (GHSA-72hv-8253-57qq, omisión de la restricción de longitud de número en el analizador no bloqueante) está incompleta. Este registro cubre la omisión restante.\n\nLa corrección anterior conectó validateIntegerLength() a una nueva función auxiliar _setIntLength() y la invocó dondequiera que se decide la porción entera de un número: llega un byte terminador, se ve un ’.’ o una ’e’/’E’, o la entrada termina dentro de un valor completamente almacenado en búfer. No se invocó en la ruta relevante para el atacante donde el analizador se queda sin entrada mientras aún está dentro del estado menor MINOR_NUMBER_INTEGER_DIGITS y devuelve NOT_AVAILABLE al llamador.\n\nComo resultado, un atacante que transmite JSON a un analizador no bloqueante en muchos fragmentos pequeños, sin enviar nunca un byte terminador, mantiene el analizador dentro de MINOR_NUMBER_INTEGER_DIGITS indefinidamente. _textBuffer.expandCurrentSegment() hace crecer el acumulador en cada fragmento mientras que validateIntegerLength() nunca se llama. El acumulador está limitado solo por maxStringLength (20 MiB por defecto) en lugar de por maxNumberLength (1000 por defecto), una amplificación de aproximadamente 20.000x sobre el límite documentado. Debido a que los valores char de Java ocupan dos bytes, una sola conexión puede ser llevada a aproximadamente 40 MiB de heap antes de que el validador finalmente se active cuando el valor se completa.\n\nEl código equivalente de la ruta de fracción es correcto: _finishFloatFraction() llama a _setFractLength() antes de su retorno NOT_AVAILABLE. La llamada faltante afecta las rutas de dígitos enteros en _startPositiveNumber(), _startNegativeNumber() y _finishNumberIntegralPart() en NonBlockingUtf8JsonParserBase.\n\nImpacto: los frameworks reactivos como Spring WebFlux/Reactor, Quarkus, Helidon y Vert.x alimentan bytes HTTP o gRPC entrantes al analizador asíncrono a medida que llegan, que es precisamente la forma de alimentación en fragmentos requerida. Los operadores que configuran StreamReadConstraints.maxNumberLength esperando que limite la memoria por valor numérico no obtienen esa garantía; la memoria se acumula por conexión concurrente y la concurrencia controlada por el atacante puede agotar el heap de la JVM. Los analizadores síncronos (UTF8StreamJsonParser, ReaderBasedJsonParser) y el analizador asíncrono que opera con entrada completa no se ven afectados.\n\nLa explotación requiere solo la capacidad de transmitir datos a un punto final de análisis; no se necesitan privilegios ni interacción del usuario.\n\nEste problema afecta a com.fasterxml.jackson.core:jackson-core desde la versión 2.15.0 hasta la 2.18.7, y desde la 2.19.0 hasta la 2.21.3, y a tools.jackson.core:jackson-core desde la 3.0.0 hasta la 3.1.3. Las versiones anteriores a la 2.15.0 no se ven afectadas, porque StreamReadConstraints -- que define la configuración maxNumberLength -- se introdujo por primera vez en jackson-core 2.15.0, por lo que no existe tal restricción para ser omitida en versiones anteriores. Tenga en cuenta que GHSA-r7wm-3cxj-wff9 establece el rango 2.x afectado sin un límite inferior. Las líneas de lanzamiento 2.22.x y 3.2.x no se ven afectadas: esas ramas se crearon después de que la confirmación de la corrección se aplicara el 21-05-2026 y por lo tanto la contienen desde sus lanzamientos iniciales (2.22.0, etiquetado el 03-06-2026, y 3.2.0, etiquetado el 08-06-2026)."
}
],
"affected": [
{
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"affectedData": [
{
"vendor": "FasterXML",
"product": "jackson-core",
"defaultStatus": "unaffected",
"collectionURL": "https://repo.maven.apache.org/maven2",
"packageName": "com.fasterxml.jackson.core:jackson-core",
"programFiles": [
"src/main/java/com/fasterxml/jackson/core/json/async/NonBlockingUtf8JsonParserBase.java"
],
"programRoutines": [
{
"name": "NonBlockingUtf8JsonParserBase._startPositiveNumber"
},
{
"name": "NonBlockingUtf8JsonParserBase._startNegativeNumber"
},
{
"name": "NonBlockingUtf8JsonParserBase._finishNumberIntegralPart"
}
],
"repo": "https://github.com/FasterXML/jackson-core",
"versions": [
{
"version": "2.15.0",
"lessThan": "2.18.8",
"versionType": "maven",
"status": "affected"
},
{
"version": "2.18.8",
"versionType": "maven",
"status": "unaffected"
},
{
"version": "2.19.0",
"lessThan": "2.21.4",
"versionType": "maven",
"status": "affected"
},
{
"version": "2.21.4",
"versionType": "maven",
"status": "unaffected"
}
]
},
{
"vendor": "FasterXML",
"product": "jackson-core",
"defaultStatus": "unaffected",
"collectionURL": "https://repo.maven.apache.org/maven2",
"packageName": "tools.jackson.core:jackson-core",
"programFiles": [
"src/main/java/tools/jackson/core/json/async/NonBlockingUtf8JsonParserBase.java"
],
"programRoutines": [
{
"name": "NonBlockingUtf8JsonParserBase._startPositiveNumber"
},
{
"name": "NonBlockingUtf8JsonParserBase._startNegativeNumber"
},
{
"name": "NonBlockingUtf8JsonParserBase._finishNumberIntegralPart"
}
],
"repo": "https://github.com/FasterXML/jackson-core",
"versions": [
{
"version": "3.0.0",
"lessThan": "3.1.4",
"versionType": "maven",
"status": "affected"
},
{
"version": "3.1.4",
"versionType": "maven",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV40": [
{
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"type": "Secondary",
"cvssData": {
"version": "4.0",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"baseScore": 8.7,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"vulnAvailabilityImpact": "HIGH",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"subAvailabilityImpact": "NONE",
"exploitMaturity": "NOT_DEFINED",
"confidentialityRequirement": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"availabilityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"valueDensity": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED"
}
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-08-04T17:53:50.672098Z",
"id": "CVE-2026-68494",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-770"
}
]
}
],
"references": [
{
"url": "https://github.com/FasterXML/jackson-core/commit/050b429804dce2a7e08f0be1b0b4c3d040fdb9cd",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/FasterXML/jackson-core/commit/4cdd529749da396cc7edf6d4a2aad41d47902641",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/FasterXML/jackson-core/commit/c5941e5aae7fd5aeac55d66933cfb82b9aabeef8",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/FasterXML/jackson-core/pull/1611",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/FasterXML/jackson-core/security/advisories/GHSA-r7wm-3cxj-wff9",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/advisories/GHSA-72hv-8253-57qq",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://www.cve.org/CVERecord?id=CVE-2026-18401",
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
},
{
"url": "https://github.com/FasterXML/jackson-core/security/advisories/GHSA-r7wm-3cxj-wff9",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
]
}