CVE-2026-77860: Software Security Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-8483-8qxh-jcf2
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CVSS 3.7
CWE-675
Published
Advisory Summary

CVE-2026-77860 is a LOW (CVSS 3.7) security vulnerability vulnerability (CWE-675: Multiple Operations on Resource in Single-Operation Context) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product performs the same operation on a resource two or more times, when the operation should only be applied once.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-77860 at a Glance

CVE Identifier CVE-2026-77860
GHSA Identifier GHSA-8483-8qxh-jcf2
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-675: Multiple Operations on Resource in Single-Operation Context
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 3.7

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

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

How to Fix CVE-2026-77860

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-2026-77860, 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-675: Multiple Operations on Resource in Single-Operation Context, where the product performs the same operation on a resource two or more times, when the operation should only be applied once. 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

In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb (CVE-2024-33655). A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice. This second query was named 'pump'. By alternating slow queries and pumps, the attacker keeps the per-client counter at or below the configured 'wait-limit' indefinitely, and can hold an arbitrary number of pending queries from a single source IP, up to the global mesh quota (num-queries-per-thread); eventually bypassing one of the counter measures introduced for DNSBomb (CVE-2024-33655). This vulnerability is present on the 'serve-expired' code path.

References

NVD — CVE-2026-77860 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77860
www.nlnetlabs.nl/downloads/unbound/c... WEB
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-77860.txt

Frequently Asked Questions

What is CVE-2026-77860?
CVE-2026-77860 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-675: Multiple Operations on Resource in Single-Operation Context.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-77860?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-77860?
CVE-2026-77860 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-77860?
CVE-2026-77860 is classified under CWE-675: Multiple Operations on Resource in Single-Operation Context (The product performs the same operation on a resource two or more times, when the operation should only be applied once.).
How can I check Maven dependencies for CVE-2026-77860?
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-8483-8qxh-jcf2",
  "modified" : "2026-09-16T09:30:26Z",
  "published" : "2026-09-16T09:30:26Z",
  "aliases" : [ "CVE-2026-77860" ],
  "details" : "In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb (CVE-2024-33655). A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice. This second query was named 'pump'. By alternating slow queries and pumps, the attacker keeps the per-client counter at or below the configured 'wait-limit' indefinitely, and can hold an arbitrary number of pending queries from a single source IP, up to the global mesh quota (num-queries-per-thread); eventually bypassing one of the counter measures introduced for DNSBomb (CVE-2024-33655). This vulnerability is present on the 'serve-expired' code path.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-77860"
  }, {
    "type" : "WEB",
    "url" : "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-77860.txt"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-675" ],
    "severity" : "LOW",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-16T09:17:05Z"
  }
}