GHSA-fmmc-742q-jg75 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in com.fasterxml.jackson.core:jackson-databind. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-fmmc-742q-jg75 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
jackson-databind polymorphic typing issue
Real-World Exposure
com.fasterxml.jackson.core:jackson-databind☕com.fasterxml.jackson.core:jackson-databind☕com.fasterxml.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
A Polymorphic Typing issue was discovered in FasterXML jackson-databind 2.0.0 prior to 2.9.10.1, 2.8.11.5, and 2.6.7.3. When Default Typing is enabled (either globally or for a specific property) for an externally exposed JSON endpoint and the service has the p6spy (3.8.6) jar in the classpath, and an attacker can find an RMI service endpoint to access, it is possible to make the service execute a malicious payload. This issue exists because of com.p6spy.engine.spy.P6DataSource mishandling.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 2.9.0&&< 2.9.10.1 | 2.9.10.1 |
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 2.7.0&&< 2.8.11.5 | 2.8.11.5 |
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | all versions | 2.6.7.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
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 2.9.10.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fmmc-742q-jg75 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-fmmc-742q-jg75 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-fmmc-742q-jg75. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Satellite 6 does not enable polymorphic unmarshmalling, which is a required configuration for the vulnerability to be used. We may update the jackson-databind dependency in a future release. Red Hat OpenStack Platform ships OpenDaylight, which contains the vulnerable jackson-databind. However, OpenDaylight does not…
Frequently Asked Questions
Is GHSA-fmmc-742q-jg75 in your dependencies?
O3 detects GHSA-fmmc-742q-jg75 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.