CVE-2026-9828

Deferred Deferred - Pending Action

Deserialization Bypass in logback-core

Publication date: 2026-05-28

Last updated on: 2026-05-29

Assigner: Switzerland Government Common Vulnerability Program

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-05-28

Last Modified

2026-05-29

Generated

2026-07-08

AI Q&A

2026-05-28

EPSS Evaluated

2026-07-06

NVD

CVE-2026-9828

EUVD

EUVD-2026-32895

Affected Vendors & Products

Vendor	Product	Version / Range
qos.ch	logback	to 1.5.32 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-502	The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Attack-Flow Graph

Executive Summary

This vulnerability is a deserialization of untrusted data issue in the QOS.CH Sarl logback logback-core module, specifically in the HardenedObjectInputStream component.

An attacker who can influence serialized data sent to SimpleSocketServer or SimpleSSLSocketServer can instantiate objects from certain classes in the java.lang and java.util packages that are not explicitly blocked.

Although the deserialization process is heavily restricted and no practical way to achieve remote code execution or significant privilege escalation has been identified, this vulnerability bypasses the intended security restrictions.

Impact Analysis

This vulnerability allows an attacker to bypass security restrictions by instantiating certain objects during deserialization.

However, since the deserialization is heavily restricted and no practical remote code execution or significant privilege escalation has been identified, the impact is limited.

The overall risk is low, as reflected by the CVSS base score of 1.2.

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