graylog2-server vulnerable to instantiation of arbitrary classes triggered by API request
Graylog is a free and open log management platform. Starting in version 2.0.0 and prior to versions 5.1.11 and 5.2.4, arbitrary classes can be loaded and instantiated using a HTTP PUT request to the `/api/system/cluster_config/` endpoint. Graylog's cluster config system uses fully qualified class names as config keys. To validate the existence of the requested class before using them, Graylog loads the class using the class loader. If a user with the appropriate permissions performs the request, arbitrary classes with 1-arg String constructors can be instantiated. This will execute arbitrary code that is run during class instantiation. In the specific use case of `java.io.File`, the behavior of the internal web-server stack will lead to information exposure by including the entire file content in the response to the REST request. Versions 5.1.11 and 5.2.4 contain a fix for this issue.
- Published
- Feb 7, 2024
- Updated
- Jun 17, 2026
- EPSS
- 34.7% · 98th percentile
- CWE
- CWE-284
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Report tools
Action score
45
Plan
Add it to your regular patch cycle.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 10 / 30 · 34.7%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 8.8
- CNA · GitHub_M
- 8.8
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| graylog | graylog | cpe:2.3:a:graylog:graylog |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- graylog graylog2.0.0 and later · before 5.1.11
- graylog graylog5.2.0 and later · before 5.2.4
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
Graylog2 graylog2-server
- >= 2.0.0, < 5.1.11, >= 5.2.0, < 5.2.4affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Maven | org.graylog2:graylog2-server | from 2.0.0 · before 5.1.11 | 5.1.11 |
| Maven | org.graylog2:graylog2-server | from 5.2.0-alpha.1 · before 5.2.4 | 5.2.4 |
Same product
graylog: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-37760A Session ID leak in the audit log in Graylog before 4.1.2 allows attackers to escalate privileges (to the access level of the leaked sessio39Monitor
- CVE-2021-37759A Session ID leak in the DEBUG log file in Graylog before 4.1.2 allows attackers to escalate privileges (to the access level of the leaked s39Monitor
- CVE-2026-1435Incorrect management of session invalidation vulnerability in Graylog Web Interface37Monitor
- CVE-2025-53106Graylog vulnerable to privilege escalation through API tokens35Monitor
- CVE-2020-15813Graylog before 3.3.3 lacks SSL Certificate Validation for LDAP servers.32Monitor
- CVE-2026-1436Improper Access Control (IDOR) vulnerability in Graylog Web Interface28Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Maven:org.graylog2:graylog2-server | 5.1.11 | Package registry (OSV) |
| Maven:org.graylog2:graylog2-server | 5.2.4 | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2026-06-29 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoC+872 d
- TodaySep 30, 2026+966 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-284 · Improper Access ControlCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Embedding Scripts within ScriptsCAPEC-19likelihood: High · High
- Malicious Logic InsertionCAPEC-441likelihood: Medium · High
- Modification of Windows Service ConfigurationCAPEC-478likelihood: Low · High
- Malicious Root CertificateCAPEC-479likelihood: Low · Low
- Intent SpoofCAPEC-502
- WebView ExposureCAPEC-503
- Data Injected During ConfigurationCAPEC-536likelihood: Low · High
- Incomplete Data Deletion in a Multi-Tenant EnvironmentCAPEC-546likelihood: Low · Medium
ATT&CK techniques
- RootkitT1014
- Obfuscated Files or Information: Embedded PayloadsT1027.009
- Boot or Logon Initialization ScriptsT1037
- Taint shared contentT1080
- Server Software Component: Terminal Services DLLT1505.005
- Pre-OS Boot:BootkitT1542.003
- Create or Modify System ProcessT1543
- Create or Modify System Process: Launch AgentT1543.001
- Create or Modify System Process:Windows ServiceT1543.003
- Create or Modify System Process: Launch DaemonT1543.004
- Event Triggered Execution:Change Default File AssociationT1546.001
- Event Triggered Execution:.bash_profile and .bashrcT1546.004
- Event Triggered Execution: Accessibility FeaturesT1546.008
- Event Triggered Execution: Installer PackagesT1546.016
- Boot or Logon Autostart ExecutionT1547
- Boot or Logon Autostart Execution:Kernel Modules and ExtensionsT1547.006
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/Graylog2/graylog2-server/blob/e458db8bf4f789d4d19f1b37f0263f910c8d036c/graylog2-server/src/main/java/org/graylog2/rest/resources/system/ClusterConfigResource.java#L208-L214
- github.com/Graylog2/graylog2-server/commit/75ef2b8d60e7d67f859b79fe712c8ae7b2e861d8
- github.com/Graylog2/graylog2-server/commit/7f8ef7fa8edf493106d5ef6f777d4da02c5194d9
Vendor advisories and official records. Exploit/PoC links are deliberately left out.