Denial of service via unbounded type ID cache
Published Sep 23, 2026 · Updated Sep 23, 2026
Uncontrolled resource consumption in affected FasterXML jackson-databind 2.x and 3.x releases allows remote attackers to exhaust process memory. TypeDeserializerBase._findDeserializer() stores attacker-supplied raw type IDs as distinct keys in the process-lifetime _deserializers map even when unknown IDs resolve to the same fallback. Exploitation requires name-based polymorphism with a fallback, attacker-influenced type IDs, and reuse of a long-lived ObjectMapper; repeated fresh IDs cause monotonic retention and eventual service interruption.
Summary
What happened
Uncontrolled resource consumption in affected FasterXML jackson-databind 2.x and 3.x releases allows remote attackers to exhaust process memory. TypeDeserializerBase._findDeserializer() stores attacker-supplied raw type IDs as distinct keys in the process-lifetime _deserializers map even when unknown IDs resolve to the same fallback. Exploitation requires name-based polymorphism with a fallback, attacker-influenced type IDs, and reuse of a long-lived ObjectMapper; repeated fresh IDs cause monotonic retention and eventual service interruption.
The record
- CVE
- CVE-2026-91776
- Published
- Sep 23, 2026
- Updated
- Sep 23, 2026
- Vendor
- FasterXML
- Product
- jackson-databind
- Classifications
- CWE-400, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 23, 2026CVE publishedPublication date reported by the CVE source.
- Sep 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.0.0 <=2.18.10
- Affected versionversion=2.19.0 <=2.21.6
- Affected versionversion=2.22.0 <=2.22.2
- Affected versionversion=3.0.0 <=3.1.6
- Affected versionversion=3.2.0 <=3.2.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Upstream distinct-type-ID cache growth proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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