CVE-2026-9828: Logback core QOS.CH Sarl Logback Logback-core Has Vulnerability

LOW
Advisory Identifier: GHSA-p47f-322f-whfh
Share
CWE-502
Published
Advisory Summary

CVE-2026-9828 is a LOW qos.ch sarl logback logback-core has vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Logback core libraries in the Maven ecosystem. The issue involves qos.ch sarl logback logback-core has a deserialization of untrusted data vulnerability. Remediation is available by upgrading affected packages to version 1.5.33.

CVE-2026-9828 at a Glance

CVE Identifier CVE-2026-9828
GHSA Identifier GHSA-p47f-322f-whfh
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Logback core
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-9828

To remediate this vulnerability, upgrade all affected Logback core dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ch.qos.logback:logback-core fixed: 1.5.33 
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-core</artifactId>
    <version>1.5.33</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=ch.qos.logback

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-9828, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=ch.qos.logback

Analyze the terminal output to locate any version of Logback core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.5.33), your application is affected.

Note: The mvn dependency:tree -Dincludes=ch.qos.logback command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Logback core, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-9828 Affected Logback core Versions

1 component(s)
Fixed Versions:
1.5.33
Product / Package Ecosystem Affected Versions Fixed Version
ch.qos.logback:logback-core
maven/ch.qos.logback/logback-core
Maven
< 1.5.33
1.5.33

References

NVD — CVE-2026-9828 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-9828
Logback core Source Repository REPOSITORY
https://github.com/qos-ch/logback
logback.qos.ch/news.html WEB
https://logback.qos.ch/news.html#1.5.33

Frequently Asked Questions

What is CVE-2026-9828?
CVE-2026-9828 is a security vulnerability in Logback core involving QOS.CH Sarl logback logback-core has a deserialization of untrusted data vulnerability under CWE-502: Deserialization of Untrusted Data.
Which Logback core versions are affected?
Affected versions include releases prior to 1.5.33 across affected packages: ch.qos.logback:logback-core.
What version fixes CVE-2026-9828?
Upgrading to 1.5.33 (or the latest patched release for your respective branch) resolves the vulnerability.
Is logback-core affected?
Yes, ch.qos.logback:logback-core is affected in releases prior to 1.5.33. Upgrade your dependency to 1.5.33 or later.
What CWE is associated with CVE-2026-9828?
CVE-2026-9828 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Maven dependencies for CVE-2026-9828?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=ch.qos.logback'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p47f-322f-whfh",
  "modified" : "2026-07-02T13:55:30Z",
  "published" : "2026-05-28T15:39:50Z",
  "aliases" : [ "CVE-2026-9828" ],
  "summary" : "QOS.CH Sarl logback logback-core has a deserialization of untrusted data vulnerability",
  "details" : "Deserialization of untrusted data vulnerability in QOS.CH Sarl logback logback-core (HardenedObjectInputStream (logback-core) modules) allows Object Injection albeit heavily restricted.\n\nMore 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.\n\nAlthough 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.\n\nThis issue affects logback: through 1.5.32 inclusive.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:P/RE:L/U:Green"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "ch.qos.logback:logback-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.5.33"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.5.32"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-9828"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/qos-ch/logback"
  }, {
    "type" : "WEB",
    "url" : "https://logback.qos.ch/news.html#1.5.33"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-02T13:55:30Z",
    "nvd_published_at" : "2026-05-28T14:16:27Z"
  }
}