CVE-2026-33691 Vulnerability Analysis & Exploit Details

CVE-2026-33691
Vulnerability Scoring

6.8
/10
High Risk

If left unpatched, CVE-2026-33691 could lead to major system disruptions or data loss.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-33691 Details

Status: Modified

Last updated: 🕘 24 Jul 2026, 21:10 UTC
Originally published on: 🕓 02 Apr 2026, 16:16 UTC

Time between publication and last update: 113 days

CVSS Release: version 3

CVSS3 Source

security-advisories@github.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2026-33691 Vulnerability Summary

CVE-2026-33691: The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0.

Assessing the Risk of CVE-2026-33691

Access Complexity Graph

The exploitability of CVE-2026-33691 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-2026-33691

CVE-2026-33691 presents a challenge to exploit due to its high attack complexity, but the absence of privilege requirements still makes it a viable target for skilled attackers. A thorough security review is advised.

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-2026-33691, 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-2026-33691, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-33691 has no significant impact on data confidentiality.
  • Integrity: High
    CVE-2026-33691 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: None
    CVE-2026-33691 does not impact system availability.

CVE-2026-33691 References

External References

CWE Common Weakness Enumeration

CWE-178

Vulnerable Configurations

  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.5:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.5:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.6:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.6:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.7:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.7:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.8:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.8:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.9:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:2.2.9:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:-:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:-:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc3:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.0:rc3:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.1:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.1:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.2:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.0.2:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:-:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:-:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc3:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.0:rc3:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.1:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.1:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.2:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.1.2:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:-:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:-:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc3:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.0:rc3:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.1:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.2.1:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:-:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:-:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.1:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.1:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.2:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.2:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.3:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.3:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.4:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.4:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.5:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.5:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.6:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.6:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.7:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.7:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.8:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:3.3.8:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:-:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:-:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.0.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.1.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.1.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.2.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.2.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.3.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.3.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.4.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.4.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.5.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.5.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.6.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.6.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.7.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.7.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.8.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.8.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.9.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.9.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.10.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.10.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.11.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.11.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.12.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.12.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.13.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.13.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.14.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.14.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.15.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.15.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.16.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.16.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.17.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.17.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.17.1:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.17.1:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.18.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.18.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.19.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.19.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.20.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.20.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.21.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.21.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.22.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.22.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.23.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.23.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.24.0:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.24.0:*:*:*:*:*:*:*
  • cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.24.1:*:*:*:*:*:*:*
    cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:4.24.1:*:*:*:*:*:*:*

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