# CVE-2026-9828: logback: Deserialization of untrusted data vulnerability in QOS.CH Sarl logback logback-core (HardenedObjectInputStream (logba...

CVE-2026-9828 is fixed in logback on 1 platform by DEBIAN-CVE-2026-9828 (version 1:1.6.3-1), released May 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-9828
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 28, 2026

## Description

Deserialization of untrusted data vulnerability in QOS.CH Sarl logback logback-core (HardenedObjectInputStream (logback-core) modules) allows Object Injection albeit heavily restricted.  More precisely, an attacker able to influence serialized data sent to  SimpleSocketServer or SimpleSSLSocketServer can instantiate objects from  classes in the java.lang and java.util packages that are not explicitly  blocked.  Although deserialization is heavily restricted by HardenedObjectInputStream and no  practical way to achieve remote code execution or significant privilege  escalation has been identified, this issue constitutes a bypass of the  intended security restrictions.    This issue affects logback: through 1.5.32 inclusive.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | logback Debian 14 | 1:1.6.3-1 | [DEBIAN-CVE-2026-9828](https://patchblox.com/security/data/fix/linux/debian-cve-2026-9828.md) | May 28, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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