Logback deserialization whitelist bypass for java.lang and java.util
Summary
| CVE | CVE-2026-9828 |
|---|---|
| State | PUBLISHED |
| Assigner | NCSC.ch |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-28 14:16:27 UTC |
| Updated | 2026-05-28 14:16:27 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 1.2 LOW from [email protected]
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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:L/U:Green
Problem Types: CWE-502 | CWE-502 CWE-502 Deserialization of untrusted data
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 1.2 | LOW | 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/C... |
| 4.0 | CNA | CVSS | 1.2 | LOW | 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/R... |
CVSS v4.0 Breakdown
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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:L/U:Green
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | QOS.CH Sarl | Logback | affected 1.5.32 maven | Not specified |
| CNA | QOS.CH Sarl | Logback | unaffected 1.5.33 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| logback.qos.ch/news.html | [email protected] | logback.qos.ch | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: York Shen https://github.com/york-shen (en)
Additional Advisory Data
Solutions
CNA: Upgrade to logback version 1.5.33.
Exploits
CNA: Given that HardenedObjectInputStream used by SimpleSocketServer and SimpleSSLSockerServer already heavily restricts the set of deserializable classes, it is unlikely that the attacker can escalate the vulnerability to gain control of the target host.