CVE-2026-66038: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-8mx4-8xfc-qr43
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CVSS 6.5
CWE-908
Published
Advisory Summary

CVE-2026-66038 is a HIGH (CVSS 6.5) security vulnerability vulnerability (CWE-908: Use of Uninitialized Resource) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses or accesses a resource that has not been initialized.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-66038 at a Glance

CVE Identifier CVE-2026-66038
GHSA Identifier GHSA-8mx4-8xfc-qr43
Severity HIGH
CVSS v3.1 Base Score 6.5
CWE Classification CWE-908: Use of Uninitialized Resource
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:R/S:U/C:H/I:N/A:N).

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

How to Fix CVE-2026-66038

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-2026-66038, 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-908: Use of Uninitialized Resource, where the product uses or accesses a resource that has not been initialized. 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

FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame output and potentially defeating ASLR in long-lived media processing services.

References

NVD — CVE-2026-66038 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66038
code.ffmpeg.org/ffmpeg/ffmpeg/commi... WEB
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c
code.ffmpeg.org/ffmpeg/ffmpeg/pulls... WEB
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626
www.vulncheck.com/advisories/ffmpeg-l... WEB
https://www.vulncheck.com/advisories/ffmpeg-lcl-zlib-video-decoder-information-disclosure-via-lcldec-c

Frequently Asked Questions

What is CVE-2026-66038?
CVE-2026-66038 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-908: Use of Uninitialized Resource.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-66038?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-66038?
CVE-2026-66038 has a CVSS v3.1 base score of 6.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-66038?
CVE-2026-66038 is classified under CWE-908: Use of Uninitialized Resource (The product uses or accesses a resource that has not been initialized.).
How can I check Maven dependencies for CVE-2026-66038?
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-8mx4-8xfc-qr43",
  "modified" : "2026-07-24T21:32:22Z",
  "published" : "2026-07-24T21:32:22Z",
  "aliases" : [ "CVE-2026-66038" ],
  "details" : "FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame output and potentially defeating ASLR in long-lived media processing services.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/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:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-66038"
  }, {
    "type" : "WEB",
    "url" : "https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c"
  }, {
    "type" : "WEB",
    "url" : "https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/ffmpeg-lcl-zlib-video-decoder-information-disclosure-via-lcldec-c"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-908" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-24T20:18:20Z"
  }
}