CVE-2020-2555
Vulnerability in the Oracle Coherence product of Oracle Fusion Middleware (component: Caching,CacheStore,Invocation).
Critical
Known exploited
- Severity
- 9.8 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 97.12%
- Chance of exploitation in the next 30 days. Higher than 99.89% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Nov 3, 2021
- Fix
- None yet
- No fixed version published
Exploited in the wild. Oracle Multiple Products Remote Code Execution Vulnerability (Oracle Multiple Products). Required action: Apply updates per vendor instructions. Due for U.S. federal agencies by May 3, 2022.
Description
Vulnerability in the Oracle Coherence product of Oracle Fusion Middleware (component: Caching,CacheStore,Invocation). Supported versions that are affected are 3.7.1.0, 12.1.3.0.0, 12.2.1.3.0 and 12.2.1.4.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via T3 to compromise Oracle Coherence. Successful attacks of this vulnerability can result in takeover of Oracle Coherence. CVSS 3.0 Base Score 9.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-502: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How to prevent it
- Architecture and Design, Implementation: If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- Implementation: When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Implementation: Explicitly define a final object() to prevent deserialization.
- Architecture and Design, Implementation: Make fields transient to protect them from deserialization. An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
- Implementation: Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
- Architecture and Design, Implementation: Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
CWE-502: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How to prevent it
- Architecture and Design, Implementation: If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- Implementation: When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Implementation: Explicitly define a final object() to prevent deserialization.
- Architecture and Design, Implementation: Make fields transient to protect them from deserialization. An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
- Implementation: Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
- Architecture and Design, Implementation: Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
- Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
References
Advisories
- packetstormsecurity.com/files/157054/Oracle-Coherence-Fusion-Middleware-Remote-Code-Executio…
- packetstormsecurity.com/files/157207/Oracle-WebLogic-Server-12.2.1.4.0-Remote-Code-Execution…
- packetstormsecurity.com/files/157795/WebLogic-Server-Deserialization-Remote-Code-Execution.html
- oracle.com/security-alerts/cpujan2020.html
- oracle.com/security-alerts/cpujan2021.html
- oracle.com/security-alerts/cpujul2020.html
- oracle.com/security-alerts/cpujul2021.html
- oracle.com/security-alerts/cpuoct2020.html
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| CVE-2026-110879 jackson-databind validates the outer class of a class-name type ID but accepts attacker-selected classes inside its generic arguments, even when those classes… | Critical | Same weakness, CWE-502 |
| GHSA-6757-hggm-hp2w vLLM: Public multimodal SHM handle forgery reaches worker-side `pickle.loads()` with insecure serialization disabled | High | Same weakness, CWE-502 |
| GHSA-673q-mjm6-r5xr Next.js: Unauthenticated Remote Code Execution in `use cache` functions returning typed arrays | Critical | Same weakness, CWE-502 |
| GHSA-c27m-942f-rcfh Microsoft Security Advisory CVE-2026-87697 - .NET and Visual Studio Remote Code Execution Vulnerability | High | Same weakness, CWE-502 |
| GHSA-4w5f-7jp2-w48g Microsoft Security Advisory CVE-2026-83520 - .NET and Visual Studio Remote Code Execution Vulnerability | High | Same weakness, CWE-502 |
| GHSA-4j9v-h7pp-725h Microsoft Security Advisory CVE-2026-70035 - .NET and Visual Studio Remote Code Execution Vulnerability | High | Same weakness, CWE-502 |
| GHSA-gqvg-gmmx-x4hm MLFLOW_ALLOW_PICKLE_DESERIALIZATION=False safety control bypassed by mlflow.statsmodels flavor — RCE via crafted model artifact | High | Same weakness, CWE-502 |
| GHSA-gx83-3vf8-gh7j jackson-databind: Comparable missing from DefaultBaseTypeLimitingValidator's unsafe base types (incomplete PolymorphicTypeValidator denylist) | Medium | Same weakness, CWE-502 |
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