CVE-2026-19565: Software Security Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-hw54-jvwm-w52c
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CVSS 3.7
CWE-341
Published
Advisory Summary

CVE-2026-19565 is a LOW (CVSS 3.7) security vulnerability vulnerability (CWE-341: Predictable from Observable State) affecting Software libraries in the Maven ecosystem. The weakness occurs when a number or object is predictable based on observations that the attacker can make about the state of the system or network, such as time, process id, etc.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-19565 at a Glance

CVE Identifier CVE-2026-19565
GHSA Identifier GHSA-hw54-jvwm-w52c
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-341: Predictable from Observable State
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:L/I:N/A:N).

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 Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-19565

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-2026-19565, 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-341: Predictable from Observable State, where a number or object is predictable based on observations that the attacker can make about the state of the system or network, such as time, process id, etc. 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

Apache::AppSamurai::Util versions through 1.01 for Perl generate predictable session authentication keys from the clock and process id in CreateSessionAuthKey. CreateSessionAuthKey runs five rounds of SHA-256, each over a fresh Time::HiRes reading formatted to six decimal places, the running digest, and the process id. CreateSession calls it with an empty key source on every login, and the optional Keysource directive is the only route to the other branch. The result is 64 hex characters. The microsecond field of the first reading takes one of a million values, the later readings follow it within microseconds, and the process id is drawn from a small range. The key is returned to the browser as the session cookie, and is combined with the configured server key to compute the session id and to encrypt the stored session data. An attacker who knows the second in which a session was created and the process id of the worker that created it can enumerate candidate keys and recover the victim's cookie, bypassing authentication for the protected resources. Each candidate has to be tried against the server, which validates the cookie with a key the attacker does not hold.

References

NVD — CVE-2026-19565 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19565
metacpan.org/release/pauldoom/ap... WEB
https://metacpan.org/release/PAULDOOM/Apache-AppSamurai-1.01/source/lib/Apache/AppSamurai.pm#L1446-1533
metacpan.org/release/pauldoom/ap... WEB
https://metacpan.org/release/PAULDOOM/Apache-AppSamurai-1.01/source/lib/Apache/AppSamurai/Util.pm#L106-135
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/08/23/4

Frequently Asked Questions

What is CVE-2026-19565?
CVE-2026-19565 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-341: Predictable from Observable State.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-19565?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-19565?
CVE-2026-19565 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:L/I:N/A:N.
What CWE is associated with CVE-2026-19565?
CVE-2026-19565 is classified under CWE-341: Predictable from Observable State (A number or object is predictable based on observations that the attacker can make about the state of the system or network, such as time, process ID, etc.).
How can I check Maven dependencies for CVE-2026-19565?
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-hw54-jvwm-w52c",
  "modified" : "2026-08-25T21:31:21Z",
  "published" : "2026-08-23T21:31:00Z",
  "aliases" : [ "CVE-2026-19565" ],
  "details" : "Apache::AppSamurai::Util versions through 1.01 for Perl generate predictable session authentication keys from the clock and process id in CreateSessionAuthKey.\n\nCreateSessionAuthKey runs five rounds of SHA-256, each over a fresh Time::HiRes reading formatted to six decimal places, the running digest, and the process id. CreateSession calls it with an empty key source on every login, and the optional Keysource directive is the only route to the other branch. The result is 64 hex characters. The microsecond field of the first reading takes one of a million values, the later readings follow it within microseconds, and the process id is drawn from a small range.\n\nThe key is returned to the browser as the session cookie, and is combined with the configured server key to compute the session id and to encrypt the stored session data. An attacker who knows the second in which a session was created and the process id of the worker that created it can enumerate candidate keys and recover the victim's cookie, bypassing authentication for the protected resources. Each candidate has to be tried against the server, which validates the cookie with a key the attacker does not hold.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-19565"
  }, {
    "type" : "WEB",
    "url" : "https://metacpan.org/release/PAULDOOM/Apache-AppSamurai-1.01/source/lib/Apache/AppSamurai.pm#L1446-1533"
  }, {
    "type" : "WEB",
    "url" : "https://metacpan.org/release/PAULDOOM/Apache-AppSamurai-1.01/source/lib/Apache/AppSamurai/Util.pm#L106-135"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/08/23/4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-341" ],
    "severity" : "LOW",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-23T20:16:50Z"
  }
}