CVE-2026-54512 | jackson-databind: PolymorphicTypeValidator bypass via generic type parameters allows arbitrary class instantiation

Exp

jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.10.0 until 2.18.8, 2.21.4, and 3.1.4, jackson-databind's PolymorphicTypeValidator (PTV) is the primary safety mechanism guarding polymorphic deserialization. When polymorphic typing is enabled and a type identifier contains generic parameters (i.e. the type ID string contains <), DatabindContext._resolveAndValidateGeneric() validates only the raw container class name (the substring before <) against the configured PTV. If the container type is approved, the method parses the full canonical type string via TypeFactory.constructFromCanonical() and returns the fully parameterized type without ever validating the nested type arguments against the PTV. The nested type arguments are then resolved, instantiated, and populated as beans during deserialization. An attacker who controls the type ID can therefore place a denied class as a generic type parameter of an allowed container — for example java.util.ArrayList<com.evil.Gadget> when only java.util.ArrayList is allow-listed. The container passes the PTV check; com.evil.Gadget is loaded via Class.forName(name, true, loader), instantiated, and its properties are set from attacker-controlled JSON. This completely bypasses an explicitly configured PTV allow-list. This vulnerability is fixed in 2.18.8, 2.21.4, and 3.1.4.

Published: 2026-06-23 Last update: 2026-06-27 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-54512 is rated High Exploit Risk (62.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.60%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-54512

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-54512

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-24 — 0.60% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-54512

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]

Weakness enumeration for CVE-2026-54512

GitHub Security Advisory for CVE-2026-54512

GHSA-j3rv-43j4-c7qm · Severity: high · Ecosystem: maven — jackson-databind has a PolymorphicTypeValidator bypass via generic type parameters that allows arbitrary class instantiation

OS Trackers for CVE-2026-54512

vendor priority summary link
debian not yet assigned CVE-2026-54512 not yet assigned priority: Debian including 1 source packages (jackson-databind), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-54512
suse high — https://www.suse.com/security/cve/CVE-2026-54512/
ubuntu medium CVE-2026-54512 medium priority: Ubuntu including 1 source packages (jackson-databind), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream): needs-triage 8. https://ubuntu.com/security/CVE-2026-54512

Affected software / configurations for CVE-2026-54512

Vendor Product Version Raw CPE
fasterxml jackson-databind >= 2.10.0, < 2.18.8 cpe:2.3:a:fasterxml:jackson-databind:*:*:*:*:*:*:*:*
fasterxml jackson-databind >= 2.19.0, < 2.21.4 cpe:2.3:a:fasterxml:jackson-databind:*:*:*:*:*:*:*:*
fasterxml jackson-databind >= 3.0.0, < 3.1.4 cpe:2.3:a:fasterxml:jackson-databind:*:*:*:*:*:*:*:*

References for CVE-2026-54512

cvelogic Threat Intelligence