CVE-2026-3256 Vulnerability Analysis & Exploit Details

CVE-2026-3256
Vulnerability Scoring

9.8
/10
Critical Risk

As a catastrophic security flaw, CVE-2026-3256 has severe implications, demanding immediate intervention.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-3256 Details

Status: Modified

Last updated: 🕖 29 Jun 2026, 07:16 UTC
Originally published on: 🕖 28 Mar 2026, 19:16 UTC

Time between publication and last update: 92 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE-2026-3256 Vulnerability Summary

CVE-2026-3256: HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults to using HTTP::Session::ID::SHA1 to generate session ids using a SHA-1 hash seeded with the built-in rand function, the high resolution epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. The distribution includes HTTP::session::ID::MD5 which contains a similar flaw, but uses the MD5 hash instead.

Assessing the Risk of CVE-2026-3256

Access Complexity Graph

The exploitability of CVE-2026-3256 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-3256

With low attack complexity and no required privileges, CVE-2026-3256 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-3256, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-3256, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-3256 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2026-3256 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: High
    CVE-2026-3256 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-3256 References

External References

CWE Common Weakness Enumeration

CWE-340

Vulnerable Configurations

  • cpe:2.3:a:ktat:http\:\:session:0.02:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.02:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.03:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.03:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.04:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.04:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.05:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.05:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.06:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.06:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.07:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.07:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.08:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.08:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.09:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.09:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.10:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.10:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.11:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.11:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.20:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.20:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.21:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.21:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.22:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.22:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.23:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.23:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.24:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.24:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.25:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.25:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.26:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.26:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.27:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.27:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.28:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.28:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.29:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.29:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.30:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.30:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.31:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.31:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.32:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.32:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.33:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.33:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.34:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.34:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.35:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.35:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.36:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.36:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.37:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.37:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.38:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.38:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.39:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.39:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.40:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.40:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.41:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.41:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.42:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.42:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.43:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.43:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.44:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.44:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.45:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.45:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.46:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.46:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.48:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.48:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.49:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.49:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.50:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.50:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.51:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.51:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.52:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.52:*:*:*:*:perl:*:*
  • cpe:2.3:a:ktat:http\:\:session:0.53:*:*:*:*:perl:*:*
    cpe:2.3:a:ktat:http\:\:session:0.53:*:*:*:*:perl:*:*

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