CVE-2026-72854: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-p5jw-mm77-f8jp
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CVSS 5.3
CWE-190
Published
Advisory Summary

CVE-2026-72854 is a MODERATE (CVSS 5.3) security vulnerability vulnerability (CWE-190: Integer Overflow or Wraparound) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-72854 at a Glance

CVE Identifier CVE-2026-72854
GHSA Identifier GHSA-p5jw-mm77-f8jp
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-190: Integer Overflow or Wraparound
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 5.3

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

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

How to Fix CVE-2026-72854

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-2026-72854, 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-190: Integer Overflow or Wraparound, where the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number. 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

msgpack_unpacker_expand_buffer in src/unpack.c, reached through the public msgpack_unpacker_reserve_buffer API, computes its new buffer size using an unchecked size_t addition of the requested size and the amount already used. The doubling loop guards its own multiplication against overflow, but the addition in the loop condition is unguarded, so a request near SIZE_MAX wraps: the loop condition is already satisfied, the allocation is performed at the small pre-wrap size, and the function returns true. The caller is told the requested capacity was reserved when it was not, so a subsequent write of the requested length overflows the heap buffer. The library's own example/lib_buffer_unpack.c demonstrates the reserve-then-write pattern, and its defensive assert comparing capacity against the request is compiled out under NDEBUG. msgpack-c's own decode entry points do not derive the reservation size from untrusted input, so reaching this requires an integration that passes an attacker-influenced length to the reservation API, such as a length-prefixed streaming transport.

References

NVD — CVE-2026-72854 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-72854
Software Source Repository REPOSITORY
https://github.com/msgpack/msgpack-c/issues/1181
Software Source Repository REPOSITORY
https://github.com/msgpack/msgpack-c
Software Source Repository REPOSITORY
https://github.com/msgpack/msgpack-c/blob/c-7.0.1/example/lib_buffer_unpack.c
Software Source Repository REPOSITORY
https://github.com/msgpack/msgpack-c/blob/c-7.0.1/include/msgpack/unpack.h#L219-L223
Software Source Repository REPOSITORY
https://github.com/msgpack/msgpack-c/blob/c-7.0.1/src/unpack.c#L429-L502
www.vulncheck.com/advisories/msgpack-... WEB
https://www.vulncheck.com/advisories/msgpack-c-integer-overflow-in-msgpack-unpacker-expand-buffer-causes-a-false-success-undersized-reservation

Frequently Asked Questions

What is CVE-2026-72854?
CVE-2026-72854 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-190: Integer Overflow or Wraparound.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-72854?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-72854?
CVE-2026-72854 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L.
What CWE is associated with CVE-2026-72854?
CVE-2026-72854 is classified under CWE-190: Integer Overflow or Wraparound (The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.).
How can I check Maven dependencies for CVE-2026-72854?
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-p5jw-mm77-f8jp",
  "modified" : "2026-08-20T21:31:28Z",
  "published" : "2026-08-20T21:31:28Z",
  "aliases" : [ "CVE-2026-72854" ],
  "details" : "msgpack_unpacker_expand_buffer in src/unpack.c, reached through the public msgpack_unpacker_reserve_buffer API, computes its new buffer size using an unchecked size_t addition of the requested size and the amount already used. The doubling loop guards its own multiplication against overflow, but the addition in the loop condition is unguarded, so a request near SIZE_MAX wraps: the loop condition is already satisfied, the allocation is performed at the small pre-wrap size, and the function returns true. The caller is told the requested capacity was reserved when it was not, so a subsequent write of the requested length overflows the heap buffer. The library's own example/lib_buffer_unpack.c demonstrates the reserve-then-write pattern, and its defensive assert comparing capacity against the request is compiled out under NDEBUG. msgpack-c's own decode entry points do not derive the reservation size from untrusted input, so reaching this requires an integration that passes an attacker-influenced length to the reservation API, such as a length-prefixed streaming transport.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/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-2026-72854"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/msgpack/msgpack-c/issues/1181"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/msgpack/msgpack-c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/msgpack/msgpack-c/blob/c-7.0.1/example/lib_buffer_unpack.c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/msgpack/msgpack-c/blob/c-7.0.1/include/msgpack/unpack.h#L219-L223"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/msgpack/msgpack-c/blob/c-7.0.1/src/unpack.c#L429-L502"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/msgpack-c-integer-overflow-in-msgpack-unpacker-expand-buffer-causes-a-false-success-undersized-reservation"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-190" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-20T19:17:01Z"
  }
}