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VulnerabilityPublished

CVE-2026-110879: FasterXML jackson-databind · Deserialization of Untrusted Data

Affects FasterXML jackson-databindSource CVE Database V5

0

Mentioned vulnerabilities

Not known to be exploited · CVSS 9.8 Critical · fixed in 2.22.4 : patch FasterXML jackson-databind as a priority.

Data as of 28 Oct 2026, 00:57 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2.22.4, 2.21.8, 2.18.12 +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade jackson-databind and FasterXML/com.fasterxml.jackson.core:jackson-databind to 2.22.4, 2.21.8 or 2.18.12; jackson-databind and FasterXML/tools.jackson.core:jackson-databind to 3.2.4 or 3.1.8.

Affected software

ProductAffectedFixed in
jackson-databindcom.fasterxml.jackson.core:jackson-databindAffected
  • >=2.22.0 <2.22.4
Fixed in
  • 2.22.4
jackson-databindcom.fasterxml.jackson.core:jackson-databindAffected
  • >=2.19.0 <2.21.8
Fixed in
  • 2.21.8
jackson-databindcom.fasterxml.jackson.core:jackson-databindAffected
  • >=2.10.0 <2.18.12
Fixed in
  • 2.18.12
jackson-databindtools.jackson.core:jackson-databindAffected
  • >=3.2.0 <3.2.4
Fixed in
  • 3.2.4
jackson-databindtools.jackson.core:jackson-databindAffected
  • >=3.0.0 <3.1.8
Fixed in
  • 3.1.8
MavenFasterXML/com.fasterxml.jackson.core:jackson-databindpkg:maven/FasterXML/com.fasterxml.jackson.core:jackson-databindOther threatsAffected
  • >=2.10.0 <2.18.12
  • >=2.19.0 <2.21.8
  • >=2.22.0 <2.22.4
Fixed in
  • 2.18.12
  • 2.21.8
  • 2.22.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

jackson-databind validates the outer class of a class-name type ID but accepts attacker-selected classes inside its generic arguments, even when those classes violate the declared type or would be rejected as direct type IDs. This bypasses the generic-argument validation added for CVE-2026-54512 (GHSA-j3rv-43j4-c7qm), of which this is an incomplete fix. DatabindContext._resolveAndValidateGeneric() checks the outer class against the declared base type and then passes each argument from the type ID to _validateTypeParameter(), which validates the argument against the outer base type rather than enforcing its corresponding declared generic binding. It also invokes validators with arguments that have not passed the subtype check those validators expect. Under the default DefaultBaseTypeLimitingValidator this accepts an unrelated class inside a generic subtype even when the same class is rejected as a direct type ID. Where an allowIfBaseType(...) rule approves the outer type, Jackson substitutes LaissezFaireSubTypeValidator, so the configured validator no longer restricts the embedded arguments. The element type of a plain array type ID such as [Lpkg.Gadget; is likewise left unvalidated once the array's base type is approved. Affected paths include annotation-based class-name polymorphism with a default Jackson 3.x JsonMapper, configured default typing in both Jackson 2.x and 3.x, and integrations that expose that default typing. The default-validator case requires no application-authored validator: with @JsonTypeInfo(use = Id.CLASS), a direct gadget type ID is rejected as "Not a subtype", while a type ID naming a generic wrapper around the same gadget is accepted and deserialized, including attacker-supplied bean properties. Where class-name default typing permits Map, a property declared as Map<String,String> accepts HashMap<FileSystemXmlApplicationContext,String>; map-key discovery then passes the attacker-controlled JSON property name to the selected class's one-string constructor. With Spring on the classpath and attacker-controlled XML the application can load, that constructor loads the XML and invokes ProcessBuilder.start() under the application account, giving arbitrary command execution. This issue affects com.fasterxml.jackson.core:jackson-databind from 2.10.0 and tools.jackson.core:jackson-databind from 3.0.0. Releases before 2.10.0 are not affected, because PolymorphicTypeValidator was introduced in jackson-databind 2.10.0.

References

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