CVE-2026-77972: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-pqwh-q74p-w7h4
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CWE-367
Published
Advisory Summary

CVE-2026-77972 is a CRITICAL security vulnerability vulnerability (CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-77972 at a Glance

CVE Identifier CVE-2026-77972
GHSA Identifier GHSA-pqwh-q74p-w7h4
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-77972

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-2026-77972, 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-367: Time-of-check Time-of-use (TOCTOU) Race Condition, where the product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. 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

Time-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected. Validation returns a verdict and not the address it approved, so the HTTP clients the library ships receive the original hostname and resolve it a second time when the request is made. An attacker who controls the authoritative DNS for a name can answer the first lookup with a permitted address and the second with a blocked one, and the request then reaches a destination validation never approved. The same window opens without an attacker whenever a name legitimately resolves to different addresses across lookups, such as short record lifetimes or rotation between several addresses. This issue affects safeurl: from 0.1.0 onward.

References

NVD — CVE-2026-77972 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77972
Security Fix Commit FIX COMMIT
https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70
cna.erlef.org/cves/cve-2026-77972... WEB
https://cna.erlef.org/cves/CVE-2026-77972.html
osv.dev/vulnerability/eef-c... WEB
https://osv.dev/vulnerability/EEF-CVE-2026-77972

Frequently Asked Questions

What is CVE-2026-77972?
CVE-2026-77972 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-77972?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-77972?
CVE-2026-77972 is classified under CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition (The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.).
How can I check Maven dependencies for CVE-2026-77972?
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-pqwh-q74p-w7h4",
  "modified" : "2026-09-15T18:32:26Z",
  "published" : "2026-09-15T18:32:26Z",
  "aliases" : [ "CVE-2026-77972" ],
  "details" : "Time-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected.\n\nValidation returns a verdict and not the address it approved, so the HTTP clients the library ships receive the original hostname and resolve it a second time when the request is made. An attacker who controls the authoritative DNS for a name can answer the first lookup with a permitted address and the second with a blocked one, and the request then reaches a destination validation never approved. The same window opens without an attacker whenever a name legitimately resolves to different addresses across lookups, such as short record lifetimes or rotation between several addresses.\n\nThis issue affects safeurl: from 0.1.0 onward.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/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-2026-77972"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70"
  }, {
    "type" : "WEB",
    "url" : "https://cna.erlef.org/cves/CVE-2026-77972.html"
  }, {
    "type" : "WEB",
    "url" : "https://osv.dev/vulnerability/EEF-CVE-2026-77972"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-367" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-15T16:17:24Z"
  }
}