FKIE_CVE-2026-91777
Vulnerability from fkie_nvd - Published: 2026-09-23 03:17 - Updated: 2026-09-23 15:17
Severity
Summary
Forward-reference completion for @JsonIdentityInfo object IDs in FasterXML jackson-databind performs a linear scan of the pending-reference accumulator for every resolved ID. The affected paths are CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference() and the equivalent implementation in MapDeserializer. When a document first creates N unresolved object-ID references in an identity-enabled collection or map and then defines those same IDs in reverse order, completion performs on the order of N * (N + 1) / 2 identity comparisons, so a shallow document whose size grows linearly causes quadratic CPU work during deserialization. The reporter instrumented equals() calls on the ID class and measured exactly 2,003,000 comparisons at N = 2,000, against zero comparisons in the pending-reference lookup path for an equally sized control in which every reference was already resolved. The input requires no deep nesting and no syntactically unusual JSON. Exploitation requires an application that deserializes attacker-influenced JSON into an identity-enabled collection or map. The fix replaces the repeated linear lookup with a keyed pending-reference structure.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://repo1.maven.org/maven2",
"defaultStatus": "unaffected",
"packageName": "com.fasterxml.jackson.core:jackson-databind",
"product": "jackson-databind",
"programRoutines": [
{
"name": "com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference"
},
{
"name": "com.fasterxml.jackson.databind.deser.std.MapDeserializer.MapReferringAccumulator.resolveForwardReference"
}
],
"repo": "https://github.com/FasterXML/jackson-databind",
"vendor": "FasterXML",
"versions": [
{
"lessThanOrEqual": "2.18.10",
"status": "affected",
"version": "2.5.0",
"versionType": "maven"
},
{
"lessThanOrEqual": "2.21.6",
"status": "affected",
"version": "2.19.0",
"versionType": "maven"
},
{
"lessThanOrEqual": "2.22.2",
"status": "affected",
"version": "2.22.0",
"versionType": "maven"
}
]
},
{
"collectionURL": "https://repo1.maven.org/maven2",
"defaultStatus": "unaffected",
"packageName": "tools.jackson.core:jackson-databind",
"product": "jackson-databind",
"programRoutines": [
{
"name": "tools.jackson.databind.deser.jdk.CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference"
},
{
"name": "tools.jackson.databind.deser.jdk.MapDeserializer.MapReferringAccumulator.resolveForwardReference"
}
],
"repo": "https://github.com/FasterXML/jackson-databind",
"vendor": "FasterXML",
"versions": [
{
"lessThanOrEqual": "3.1.6",
"status": "affected",
"version": "3.0.0",
"versionType": "maven"
},
{
"lessThanOrEqual": "3.2.2",
"status": "affected",
"version": "3.2.0",
"versionType": "maven"
}
]
}
],
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Forward-reference completion for @JsonIdentityInfo object IDs in FasterXML jackson-databind performs a linear scan of the pending-reference accumulator for every resolved ID. The affected paths are CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference() and the equivalent implementation in MapDeserializer. When a document first creates N unresolved object-ID references in an identity-enabled collection or map and then defines those same IDs in reverse order, completion performs on the order of N * (N + 1) / 2 identity comparisons, so a shallow document whose size grows linearly causes quadratic CPU work during deserialization. The reporter instrumented equals() calls on the ID class and measured exactly 2,003,000 comparisons at N = 2,000, against zero comparisons in the pending-reference lookup path for an equally sized control in which every reference was already resolved. The input requires no deep nesting and no syntactically unusual JSON. Exploitation requires an application that deserializes attacker-influenced JSON into an identity-enabled collection or map. The fix replaces the repeated linear lookup with a keyed pending-reference structure."
}
],
"id": "CVE-2026-91777",
"lastModified": "2026-09-23T15:17:25.223",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"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"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-91777",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-23T14:04:51.226591Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-23T03:17:04.783",
"references": [
{
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"url": "https://github.com/FasterXML/jackson-databind/issues/6204"
},
{
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-cxp5-3px4-pw24"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-cxp5-3px4-pw24"
}
],
"sourceIdentifier": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"vulnStatus": "Received",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-400"
}
],
"source": "36c7be3b-2937-45df-85ea-ca7133ea542c",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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