CVE-2026-59888 is a medium-severity (CVSS 6.5) CWE-915 vulnerability in com.fasterxml.jackson.core:jackson-databind. O3 Security confirms whether CVE-2026-59888 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
jackson-databind: @JsonIgnore on a Record property is bypassed with a PropertyNamingStrategy
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-59888.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-59888 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 369,023 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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
jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.15.0 until 2.18.8, 2.21.4, and 3.1.4, Java Records using a PropertyNamingStrategy can bypass @JsonIgnore because POJOPropertiesCollector._removeUnwantedIgnorals() records an ignored component under its original implicit name before _renameUsing() applies the naming strategy, allowing the renamed JSON key to be assigned to the Record constructor parameter. This issue is fixed in versions 2.18.8, 2.21.4, and 3.1.4.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 2.15.0&&< 2.18.8 | 2.18.8 |
| ☕Maven | com.fasterxml.jackson.core:jackson-databind | ≥ 2.19.0&&< 2.21.4 | 2.21.4 |
| ☕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 2.18.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59888 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 CVE-2026-59888 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 CVE-2026-59888. 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.
Moderate impact. This flaw in jackson-databind allows an attacker to bypass the @JsonIgnore annotation when deserializing Java Records that utilize a PropertyNamingStrategy. An untrusted client could exploit this to assign values to internal or privileged Record constructor parameters, potentially leading to…
Frequently Asked Questions
Is CVE-2026-59888 in your dependencies?
O3 detects CVE-2026-59888 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.