SB2026110746 - Multiple vulnerabilities in Oracle Communications Cloud Native Core Network Exposure Function

Description

This security bulletin contains information about 7 vulnerabilities.

1) Input validation error (CVE-ID: CVE-2026-27135)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to missing state validation in the nghttp2 session handling logic when processing malformed frames after session termination has been initiated. A remote attacker can send specially crafted frames to cause a denial of service.

For PRIORITY_UPDATE and ALTSVC frames, the affected extension types must be explicitly enabled. Builds with assertions disabled may not crash under the same conditions.

2) Improper handling of highly compressed data (CVE-ID: CVE-2026-21441)

CWE-ID: CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the application does not properly handle highly compressed data when sending HTTP redirect responses. A remote attacker can multiple large requests to the application, consume all available CPU and memory resources and perform a denial of service attack.

3) Resource exhaustion (CVE-ID: CVE-2026-42587)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in HttpContentDecompressor and DelegatingDecompressorFrameListener when processing compressed HTTP request bodies with Content-Encoding set to br, zstd, or snappy. A remote attacker can send a specially crafted compressed payload to cause a denial of service.

The configured maxAllocation limit is enforced for gzip and deflate, but is silently ignored for brotli, zstd, and snappy. The issue affects both HTTP/1.1 and HTTP/2 handling.

4) Improper Encoding or Escaping of Output (CVE-ID: CVE-2026-34481)

CWE-ID: CWE-116 - Improper Encoding or Escaping of Output

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause downstream log processing systems to reject or fail to index affected records.

The vulnerability exists due to improper serialization of non-finite floating-point values in JsonTemplateLayout when processing log events containing a MapMessage with an attacker-controlled floating-point value. A remote attacker can supply a non-finite floating-point value to cause downstream log processing systems to reject or fail to index affected records.

Exploitation is possible only if the application uses JsonTemplateLayout and logs a MapMessage containing the attacker-controlled value.

5) Improper input validation (CVE-ID: CVE-2025-8837)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local authenticated user to execute arbitrary code.

The vulnerability exists due to improper input validation within the ATS Framework (JasPer) component in Oracle Communications Cloud Native Core Service Communication Proxy. A local authenticated user can exploit this vulnerability to execute arbitrary code.

6) Buffer overflow (CVE-ID: CVE-2025-9900)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing image files. A remote attacker can create a specially crafted image file, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

7) Input validation error (CVE-ID: CVE-2025-31651)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to bypass rewrite rules.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can send a specially crafted input to the application and bypass configured rewrite rules.

Remediation

Install update from vendor's website.

References

• https://www.oracle.com/security-alerts/cpujul2026.html