CVE-2026-18798: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-3j55-qf57-hqc2
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CVSS 7.5
CWE-415
Published
Advisory Summary

CVE-2026-18798 is a HIGH (CVSS 7.5) security vulnerability vulnerability (CWE-415: Double Free) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product calls free() twice on the same memory address.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-18798 at a Glance

CVE Identifier CVE-2026-18798
GHSA Identifier GHSA-3j55-qf57-hqc2
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-415: Double Free
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-18798

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

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

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-18798, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

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

Note: The mvn dependency:tree 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-415: Double Free, where the product calls free() twice on the same memory address. In Software, 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

Issue summary: QUIC server may double free QRX (QUIC record layer RX) object when channel creation fails for initial packet. Impact summary: Double free leads to heap corruption, which typically results in termination of QUIC server process, leading to Denial of Service. There is so far no evidence that this double free is exploitable for remote code execution, thus it is considered highly improbable. CWE: CWE-415: Double Free Description: In order to validate initial packet, OpenSSL QUIC stack default packet handler (port_default_packet_handler()) creates a so-called QRX object. If the initial packet validates successfully with QRX object, the default packet handler proceeds to channel (connection object) creation. The QRX object used for packet validation is passed to port_bind_channel(), so it becomes part of the newly created connection. If port_bind_channel() fails, then it also frees the QRX object. Once port_bind_channel() returns, the port_default_packet_handler() detects the failure and proceeds to the error branch, where the same QRX object is freed for the second time. The failure in port_bind_channel() function can be induced with a relatively low effort by a malformed (non RFC 9000 compliant) INITIAL packet. If the packet carries DCID (destination connection ID) which is shorter than 8 bytes, then port_bind_channel() jumps to the error path after ossl_quic_lcidm_enrol_odcid() detects that the DCID has invalid length. FIPS impact: no The FIPS module is not affected, as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

References

NVD — CVE-2026-18798 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18798
Security Fix Commit FIX COMMIT
https://github.com/openssl/openssl/commit/70cebd74d3592f5272945501b58a60374c4e13af
Security Fix Commit FIX COMMIT
https://github.com/openssl/openssl/commit/967582d5037f01a26b6d19beae19af62a1b15c3c
Security Fix Commit FIX COMMIT
https://github.com/openssl/openssl/commit/a14a1deac403522fbeafabcb198503cf6caa7dc4
openssl-library.org/news/secadv/2026082... WEB
https://openssl-library.org/news/secadv/20260825.txt

Frequently Asked Questions

What is CVE-2026-18798?
CVE-2026-18798 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-415: Double Free.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-18798?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-18798?
CVE-2026-18798 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-18798?
CVE-2026-18798 is classified under CWE-415: Double Free (The product calls free() twice on the same memory address.).
How can I check Maven dependencies for CVE-2026-18798?
Run the dependency tree command: 'mvn dependency:tree'. 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-3j55-qf57-hqc2",
  "modified" : "2026-08-25T15:32:58Z",
  "published" : "2026-08-25T15:32:58Z",
  "aliases" : [ "CVE-2026-18798" ],
  "details" : "Issue summary: QUIC server may double free QRX (QUIC record layer RX) object\nwhen channel creation fails for initial packet.\n\nImpact summary: Double free leads to heap corruption, which typically results in \ntermination of QUIC server process, leading to Denial of Service. There is so\nfar no evidence that this double free is exploitable for remote code execution,\nthus it is considered highly improbable.\n\nCWE: CWE-415: Double Free\n\nDescription: In order to validate initial packet, OpenSSL QUIC stack default\npacket handler (port_default_packet_handler()) creates a so-called QRX object.\nIf the initial packet validates successfully with QRX object, the default packet\nhandler proceeds to channel (connection object) creation. The QRX object used\nfor packet validation is passed to port_bind_channel(), so it becomes part of\nthe newly created connection. If port_bind_channel() fails, then it also frees\nthe QRX object. Once port_bind_channel() returns, the port_default_packet_handler()\ndetects the failure and proceeds to the error branch, where the same QRX object is\nfreed for the second time.\n\nThe failure in port_bind_channel() function can be induced with a relatively\nlow effort by a malformed (non RFC 9000 compliant) INITIAL packet. If the packet\ncarries DCID (destination connection ID) which is shorter than 8 bytes, then\nport_bind_channel() jumps to the error path after ossl_quic_lcidm_enrol_odcid()\ndetects that the DCID has invalid length.\n\nFIPS impact: no\nThe FIPS module is not affected, as the QUIC implementation is outside of\nthe OpenSSL FIPS module boundary.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18798"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openssl/openssl/commit/70cebd74d3592f5272945501b58a60374c4e13af"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openssl/openssl/commit/967582d5037f01a26b6d19beae19af62a1b15c3c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openssl/openssl/commit/a14a1deac403522fbeafabcb198503cf6caa7dc4"
  }, {
    "type" : "WEB",
    "url" : "https://openssl-library.org/news/secadv/20260825.txt"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-415" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-25T13:17:49Z"
  }
}