CVE-2021-43838 Vulnerability Analysis & Exploit Details

CVE-2021-43838
Vulnerability Scoring

5.3
/10
Significant Risk

Security assessments indicate that CVE-2021-43838 presents a notable risk, potentially requiring prompt mitigation.

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-2021-43838 Details

Status: Modified

Last updated: 🕕 21 Nov 2024, 06:29 UTC
Originally published on: 🕖 17 Dec 2021, 19:15 UTC

Time between publication and last update: 1069 days

CVSS Release: version 3

CVSS3 Source

security-advisories@github.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2021-43838 Vulnerability Summary

CVE-2021-43838: jsx-slack is a library for building JSON objects for Slack Block Kit surfaces from JSX. In versions prior to 4.5.1 users are vulnerable to a regular expression denial-of-service (ReDoS) attack. If attacker can put a lot of JSX elements into `<blockquote>` tag, an internal regular expression for escaping characters may consume an excessive amount of computing resources. jsx-slack v4.5.1 has patched to a regex for escaping blockquote characters. Users are advised to upgrade as soon as possible.

Assessing the Risk of CVE-2021-43838

Access Complexity Graph

The exploitability of CVE-2021-43838 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-2021-43838

With low attack complexity and no required privileges, CVE-2021-43838 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-2021-43838, 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-2021-43838, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2021-43838 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2021-43838 poses no threat to data integrity.
  • Availability: Low
    CVE-2021-43838 may slightly degrade system performance without fully affecting service availability.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.101% (probability of exploit)

EPSS Percentile: 43.67% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 56.33% of others.

CVE-2021-43838 References

External References

CWE Common Weakness Enumeration

CWE-1333

CAPEC Common Attack Pattern Enumeration and Classification

  • Regular Expression Exponential Blowup CAPEC-492 An adversary may execute an attack on a program that uses a poor Regular Expression(Regex) implementation by choosing input that results in an extreme situation for the Regex. A typical extreme situation operates at exponential time compared to the input size. This is due to most implementations using a Nondeterministic Finite Automaton(NFA) state machine to be built by the Regex algorithm since NFA allows backtracking and thus more complex regular expressions.

Vulnerable Configurations

  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.1.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.1.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.2.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.2.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.3.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.3.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.3:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.4.3:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.5.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.5.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.5.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.5.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.6.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.6.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.7.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.7.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.8.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.8.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.8.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.8.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.9.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.10.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.11.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.11.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.11.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.11.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:0.12.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:0.12.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.0.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.0.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.1.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.1.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.2.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.2.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.3.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.3.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.3.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.3.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.4.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.4.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.5.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.5.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.5.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.5.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.6.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.6.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:1.7.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:1.7.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:-:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:-:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta0:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta0:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta1:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta1:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta2:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:beta2:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha0:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha0:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha1:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha1:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha2:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.0.0:alpha2:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.1.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.1.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.2.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.2.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.2.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.2.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.3.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.3.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.4.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.4.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.5.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.5.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.5.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.5.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:2.6.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:2.6.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:3.0.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:3.0.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.0.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.0.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.1.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.1.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.2.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.2.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.2.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.2.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.3.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.3.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.3:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.4.3:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.5.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.5.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:jsx-slack_project:jsx-slack:4.5.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:jsx-slack_project:jsx-slack:4.5.1:*:*:*:*:node.js:*:*

Protect Your Infrastructure against CVE-2021-43838: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2024-43107 – Improper Certificate Validation (CWE-295) in the Gallagher Milestone Integration Plugin (MIP) permits unauthenticated messages (e.g. alarm events) ...
  • CVE-2024-41724 – Improper Certificate Validation (CWE-295) in the Gallagher Command Centre SALTO integration allowed an attacker to spoof the SALTO server. Thi...
  • CVE-2025-2133 – A vulnerability classified as problematic was found in ftcms 2.1. Affected by this vulnerability is an unknown functionality of the file /admin/ind...
  • CVE-2025-2132 – A vulnerability classified as critical has been found in ftcms 2.1. Affected is an unknown function of the file /admin/index.php/web/ajax_all_lists...
  • CVE-2025-2131 – A vulnerability was found in dayrui XunRuiCMS up to 4.6.3. It has been rated as problematic. This issue affects some unknown processing of the comp...