HighCVE-2026-91776

    jackson-databind retains every unknown raw type ID (CVE-2026-91776)

    Published Last modified Sources: Red Hat, BSI, OSV, CVE.org, Hersteller, SUSE

    What is affected, what to do

    A flaw was found in jackson-databind. A remote attacker can exploit this vulnerability by repeatedly supplying distinct, unrecognized type identifiers to an application configured with name-based polymorphism and a fallback deserializer.

    An exploit is publicly available. Update Jackson to version 2.21.7.

    Affected
    • FasterXML Jackson-databind lte 2.0.0..2.18.10
    • FasterXML Jackson-databind lte 2.19.0..2.21.6
    • FasterXML Jackson-databind lte 2.22.0..2.22.2
    • FasterXML Jackson-databind lte 3.0.0..3.1.6
    • FasterXML Jackson-databind lte 3.2.0..3.2.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Red Hat, BSI, OSV, CVE.org, Hersteller, SUSE

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 41.9

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    80.08 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    PoC (publicly reported)
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.5 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    41.9
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: proof of concept · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 23 September 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-400

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in jackson-databind. A remote attacker can exploit this vulnerability by repeatedly supplying distinct, unrecognized type identifiers to an application configured with name-based polymorphism and a fallback deserializer. This action causes the TypeDeserializerBase component to retain every unknown type ID in an unbounded cache, leading to monotonic memory consumption. Over time, this uncontrolled resource consumption can result in a Denial of Service (DoS) due to memory exhaustion.

    Source: redhat_csaf, BSI WID Portal, BSI CSAF, OSV (Open Source Vulnerabilities), cvelistv5, GitHub Security Advisories, NVD (NIST), suse_csaf

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    FasterXMLjackson-databind
    • 3.2.0 – ≤ 3.2.2
    • 2.22.0 – ≤ 2.22.2
    • 2.19.0 – ≤ 2.21.6
    • 3.0.0 – ≤ 3.1.6
    • 2.0.0 – ≤ 2.18.10
    • —
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    FasterXMLJackson
    • < 2.21.7
    • < 2.22.3
    • < 2.18.11
    • < 3.2.3
    • 2.21.7
    • 2.22.3
    • 2.18.11
    • 3.2.3
    OracleFusion Middleware
    • 4.0.0-4.5.5
    • 12.2.1.4.0
    • 14.1.2.0.0
    • 15.1.1.0.0
    • 3.0.0-3.2.21
    • 8.5.8
    • 14.1.1.0.0
    • 14.1.2.1.0
    • 27.0.0
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    mavencom.fasterxml.jackson.core:jackson-databind
    • 2.21.3
    • 2.7.1
    • 2.4.1.1
    • 2.11.3
    • 2.12.0
    • 2.22.1
    • 2.3.0
    • 2.12.5
    • 2.12.0-rc1
    • 2.17.2
    • 2.3.3
    • 2.9.10
    • 2.6.7.2
    • 2.21.6
    • 2.18.6
    • 2.19.2
    • 2.21.5
    • 2.0.2
    • 2.15.4
    • 2.10.3
    • 2.3.5
    • 2.15.3
    • 2.14.1
    • 2.18.0
    • 2.8.0.rc2
    • 2.8.7
    • 2.6.6
    • 2.3.0-rc1
    • 2.4.5
    • 2.7.0-rc1
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    Vendors and products

    Weakness classes (CWE)

    • CWE-400Uncontrolled Resource Consumption

      Class

      The product does not properly control the allocation and maintenance of a limited resource.

      Entry at MITRE CWE-400

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CIRCL SightingsGitHub Security Advisories (opens in a new tab)PoC (publicly reported)reported, not verified

    References & sources

    • github.comGHSA-wv8q-qhhj-9h54Vendor advisory
    • github.comFasterXML/jackson-databind#6203Patch
    • NVD (NIST)vuln/detail/CVE-2026-91776advisory
    • github.comFasterXML/jackson-databind/commit/2870d1d6dc1b7e1c07ee11dd5b04a…web
    • github.comFasterXML/jackson-databindpackage
    • github.comFasterXML/jackson-databind/releases/tag/jackson-databind-2.18.11web
    • github.comFasterXML/jackson-databind/releases/tag/jackson-databind-2.21.7web
    • github.comFasterXML/jackson-databind/releases/tag/jackson-databind-2.22.3web
    • github.comFasterXML/jackson-databind/releases/tag/jackson-databind-3.1.7web
    • github.comFasterXML/jackson-databind/releases/tag/jackson-databind-3.2.3web

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: proof of concept, automatable: yes

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-wv8q-qhhj-9h54
      SSVC assessmentadded
      —
      {"id":"CVE-2026-91776","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-09-23T14:02:42.582789Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Received36c7be3b…

      CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

      Weakness type: CWE-400

      Description added or changed

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      TypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw, attacker-supplied type ID. When name-based polymorphism is configured with a fallback, for example @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), every distinct unrecognized type ID resolves to the same fallback deserializer but is retained as its own key in the _deserializers map. That map has no configurable bound and lives for the lifetime of the type deserializer, so an attacker who can repeatedly supply fresh unknown type IDs causes monotonic memory retention across requests. The reporter observed 10,000 retained entries from 10,000 distinct unknown IDs, against a single entry for a control that repeated one unknown ID the same number of times, isolating attacker-controlled key cardinality from request volume. Exploitation requires an application that enables name-based polymorphism with a defaultImpl or equivalent fallback, accepts attacker-influenced type IDs, and reuses a long-lived ObjectMapper across requests. The fix stops caching fallback resolutions for unrecognized IDs and bounds both the number of cached entries and the length of a cacheable type ID.
      CVSSadded
      —
      AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-400
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/91xxx/CVE-2026-91776.json">CVE-2026-91776</a>
      Referenceadded
      —
      https://github.com/FasterXML/jackson-databind/issues/6203
      Referenceadded
      —
      https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-wv8q-qhhj-9h54

      Source identifier: 36c7be3b-2937-45df-85ea-ca7133ea542c

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