# CVE-2026-91776: jackson-databind: TypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw... CVE-2026-91776 is fixed in 5 products on 1 platform, first by SUSE-SU-2026:4394-1, released September 29, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-91776 - Priority: High - CVSS: 7.5 (high) - EPSS: 0.0049 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 23, 2026 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | jackson-annotations opensuse-leap 16.0 | 2.18.11-160000.1.1 | [OPENSUSE-SU-2026:22034-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22034-1.md) | Oct 6, 2026 | | Linux | jackson-annotations sles 15.6 | 2.18.11-150200.3.28.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-annotations sles 15.7 | 2.18.11-150200.3.28.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-annotations sles 16.0 | 2.18.11-160000.1.1 | [SUSE-SU-2026:24149-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24149-1.md) | Oct 6, 2026 | | Linux | jackson-core opensuse-leap 16.0 | 2.18.11-160000.1.1 | [OPENSUSE-SU-2026:22034-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22034-1.md) | Oct 6, 2026 | | Linux | jackson-core sles 15.6 | 2.18.11-150200.3.30.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-core sles 15.7 | 2.18.11-150200.3.30.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-core sles 16.0 | 2.18.11-160000.1.1 | [SUSE-SU-2026:24149-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24149-1.md) | Oct 6, 2026 | | Linux | jackson-databind Debian 14 | 2.18.11-1 | [DEBIAN-CVE-2026-91776](https://patchblox.com/security/data/fix/linux/debian-cve-2026-91776.md) | Oct 20, 2026 | | Linux | jackson-databind amzn 2023 | 2.21.7-1.amzn2023.0.1 | [ALAS2023-2026-3305](https://patchblox.com/security/data/fix/linux/alas2023-2026-3305.md) | Nov 7, 2026 | | Linux | jackson-databind opensuse-leap 16.0 | 2.18.11-160000.1.1 | [OPENSUSE-SU-2026:22034-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22034-1.md) | Oct 6, 2026 | | Linux | jackson-databind sles 15.6 | 2.18.11-150200.3.36.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-databind sles 15.7 | 2.18.11-150200.3.36.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-databind sles 16.0 | 2.18.11-160000.1.1 | [SUSE-SU-2026:24149-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24149-1.md) | Oct 6, 2026 | | Linux | jackson-dataformat-xml sles 15.6 | 2.18.11-150200.5.8.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-dataformat-xml sles 15.7 | 2.18.11-150200.5.8.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-dataformats-binary sles 15.6 | 2.18.11-150200.3.29.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | | Linux | jackson-dataformats-binary sles 15.7 | 2.18.11-150200.3.29.1 | [SUSE-SU-2026:4394-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4394-1.md) | Sep 29, 2026 | --- Data as of 2026-11-09T01:18:40Z UTC. 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