jackson-databind: InetSocketAddress deserialization triggers eager DNS resolution (SSRF)
Date: 2026-06
Affected: maven/tools.jackson.core:jackson-databind, maven/tools.jackson.core:jackson-databind, maven/com.fasterxml.jackson.core:jackson-databind
Attack vector: deserialization
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2026-54514
CWE: CWE-918
CVSS: 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)

## Summary `JDKFromStringDeserializer` constructed `InetSocketAddress` with `new InetSocketAddress(host, port)`, which performs eager DNS name resolution for hostname inputs at deserialization time. An application that binds untrusted JSON into a type containing an `InetSocketAddress` field issues an attacker-chosen DNS query during `readValue`, before any application-level validation or connect logic. The fix uses `InetSocketAddress.createUnresolved(host, port)`, deferring DNS to an explicit connect. ## Impact An attacker controlling JSON deserialized into an `InetSocketAddress`-bearing type can force outbound DNS lookups for attacker-chosen hostnames at deserialization time (SSRF / DNS-based out-of-band interaction / internal-resolver probing), purely from binding. ## Affected / Patched (verified via `git tag --contains` on `1f5a103`) - 2.18 line: `>= 2.18.0, < 2.18.8` -> fixed in **2.18.8** - 2.19-2.21 line: `>= 2.19.0, < 2.21.4` -> fixed in **2.21.4** - 3.x line: `>= 3.0.0, < 3.1.4` -> fixed in **3.1.4** ## Severity / CWE Maintainer: minor. Reporter: LOW. CWE-918 (SSRF). ## Upstream fix FasterXML/jackson-databind#5951 ("Improve InetSocketAddress deserialization"). Released 2026-06-04 in 2.18.8 / 2.21.4 / 3.1.4. ## Credits Omkhar Arasaratnam (@omkhar) - finder.


Mitigations:

Architectural layers (MAESTRO):