GHSA-9fxm-vc8v-hj55
MEDIUMjackson-databind's renamed @JsonIgnore'd setters can deserialize via private fields
Blast Radius
com.fasterxml.jackson.core:jackson-databind☕com.fasterxml.jackson.core:jackson-databind☕tools.jackson.core:jackson-databindReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
POJOPropertiesCollector._renameProperties() allows a property with @JsonProperty("renamed") on the getter and @JsonIgnore on the setter to be renamed rather than dropped. With MapperFeature.INFER_PROPERTY_MUTATORS enabled (default), the private backing field is retained; during deserialization BeanDeserializerFactory.addBeanProps() sees hasField()==true, builds a FieldProperty, and makes the backing field writable. An attacker supplying the renamed JSON key writes the backing field directly, bypassing the @JsonIgnore on the setter.
Impact
POJOs combining a renamed getter with an ignored setter (a read-only-over-the-wire pattern) have that field silently set from attacker input (property tampering / mass assignment). Not a general gadget; no RCE.
Affected / Patched (verified via git tag --contains)
- 2.21 line:
>= 2.21.0, < 2.21.4-> fixed in 2.21.4 (backportc3d56dd, #5968) - 3.x line:
>= 3.0.0, < 3.1.4-> fixed in 3.1.4 (#5967,e88cb17)
Severity / CWE
Maintainer: minor. Reporter: HIGH. CWE-915.
Credits
Omkhar Arasaratnam (@omkhar) - finder.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 2.21.0&&< 2.21.4 | 2.21.4 |
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 3.0.0&&< 3.1.4 | 3.1.4 |
| ☕Maven | tools.jackson.core:jackson-databind | ≥ 3.0.0&&< 3.1.4 | 3.1.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.fasterxml.jackson.core:jackson-databind. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update com.fasterxml.jackson.core:jackson-databind to 2.21.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9fxm-vc8v-hj55 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-9fxm-vc8v-hj55 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9fxm-vc8v-hj55. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9fxm-vc8v-hj55 in your dependencies?
O3 detects GHSA-9fxm-vc8v-hj55 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.