CVE-2026-107569: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-95hv-g278-w9p8
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CVSS 7.5
CWE-606
Published
Advisory Summary

CVE-2026-107569 is a HIGH (CVSS 7.5) security vulnerability vulnerability (CWE-606: Unchecked Input for Loop Condition) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-107569 at a Glance

CVE Identifier CVE-2026-107569
GHSA Identifier GHSA-95hv-g278-w9p8
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-606: Unchecked Input for Loop Condition
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-2026-107569

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-2026-107569, 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-606: Unchecked Input for Loop Condition, where the product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping. 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

Unchecked input for a loop condition in Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to stop the server carrying mail. The server bounds the mail it generates in response to a message - a rule forward, reply or copy, an account forward, a Sieve redirect, vacation or notify, a bounce, an out-of-office reply - by a counter it carries in the message's X-hMailServer-LoopCount header, and makes no more once the counter reaches the configured rule loop limit (5 by default); that is what ends a forwarding or auto-reply cycle in a bounded number of hops. X-hMailServer-LoopCount is an ordinary header that is not stripped from mail arriving from outside, and the server read it with a signed conversion and no validation, so a count below zero passed every test against the limit: a sender who sets X-hMailServer-LoopCount to a negative value, or on the Linux builds to a value above the 32-bit signed range that the conversion wraps to a negative one, lifts the bound, and a message that enters a generated-mail cycle then loops up to about two thousand million times, each hop a queued message and a delivery, filling the queue and disk and stopping mail service. The Sieve notify action (from 6.2.22) consulted no limit at all, and its increment of the count could overflow a signed integer; and an account could reset the counter on its own mail through a Sieve editheader of the header (from 6.2.22) or a rule Set header value action (all versions) ahead of a forward or redirect.

References

NVD — CVE-2026-107569 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-107569
gitlab.com/hmailserver/hmailse... WEB
https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7
gitlab.com/hmailserver/hmailse... WEB
https://gitlab.com/hmailserver/hmailserver/-/work_items/81

Frequently Asked Questions

What is CVE-2026-107569?
CVE-2026-107569 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-606: Unchecked Input for Loop Condition.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-107569?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-107569?
CVE-2026-107569 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-2026-107569?
CVE-2026-107569 is classified under CWE-606: Unchecked Input for Loop Condition (The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.).
How can I check Maven dependencies for CVE-2026-107569?
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-95hv-g278-w9p8",
  "modified" : "2026-10-19T18:32:11Z",
  "published" : "2026-10-19T18:32:11Z",
  "aliases" : [ "CVE-2026-107569" ],
  "details" : "Unchecked input for a loop condition in Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to stop the server carrying mail. The server bounds the mail it generates in response to a message - a rule forward, reply or copy, an account forward, a Sieve redirect, vacation or notify, a bounce, an out-of-office reply - by a counter it carries in the message's X-hMailServer-LoopCount header, and makes no more once the counter reaches the configured rule loop limit (5 by default); that is what ends a forwarding or auto-reply cycle in a bounded number of hops. X-hMailServer-LoopCount is an ordinary header that is not stripped from mail arriving from outside, and the server read it with a signed conversion and no validation, so a count below zero passed every test against the limit: a sender who sets X-hMailServer-LoopCount to a negative value, or on the Linux builds to a value above the 32-bit signed range that the conversion wraps to a negative one, lifts the bound, and a message that enters a generated-mail cycle then loops up to about two thousand million times, each hop a queued message and a delivery, filling the queue and disk and stopping mail service. The Sieve notify action (from 6.2.22) consulted no limit at all, and its increment of the count could overflow a signed integer; and an account could reset the counter on its own mail through a Sieve editheader of the header (from 6.2.22) or a rule Set header value action (all versions) ahead of a forward or redirect.",
  "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-2026-107569"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/hmailserver/hmailserver/-/work_items/81"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-606" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-19T16:17:01Z"
  }
}