CVE-2020-26263 Vulnerability Analysis & Exploit Details

CVE-2020-26263
Vulnerability Scoring

7.5
/10
Very High Risk

Highly exploitable, CVE-2020-26263 poses a critical security risk that could lead to severe breaches.

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-2020-26263 Details

Status: Analyzed

Last updated: 🕓 23 Dec 2020, 16:09 UTC
Originally published on: 🕔 21 Dec 2020, 17:15 UTC

Time between publication and last update: 1 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:N/A:N

CVE-2020-26263 Vulnerability Summary

CVE-2020-26263: tlslite-ng is an open source python library that implements SSL and TLS cryptographic protocols. In tlslite-ng before versions 0.7.6 and 0.8.0-alpha39, the code that performs decryption and padding check in RSA PKCS#1 v1.5 decryption is data dependant. In particular, the code has multiple ways in which it leaks information about the decrypted ciphertext. It aborts as soon as the plaintext doesn't start with 0x00, 0x02. All TLS servers that enable RSA key exchange as well as applications that use the RSA decryption API directly are vulnerable. This is patched in versions 0.7.6 and 0.8.0-alpha39. Note: the patches depend on Python processing the individual bytes in side-channel free manner, this is known to not the case (see reference). As such, users that require side-channel resistance are recommended to use different TLS implementations, as stated in the security policy of tlslite-ng.

Assessing the Risk of CVE-2020-26263

Access Complexity Graph

The exploitability of CVE-2020-26263 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-2020-26263

With low attack complexity and no required privileges, CVE-2020-26263 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-2020-26263, 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-2020-26263, 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-2020-26263 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: None
    CVE-2020-26263 poses no threat to data integrity.
  • Availability: None
    CVE-2020-26263 does not impact system availability.

Exploit Prediction Scoring System (EPSS)

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

EPSS Score: 0.604% (probability of exploit)

EPSS Percentile: 78.83% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 21.17% of others.

CVE-2020-26263 References

External References

CWE Common Weakness Enumeration

CWE-326

CAPEC Common Attack Pattern Enumeration and Classification

  • Brute Force CAPEC-112 In this attack, some asset (information, functionality, identity, etc.) is protected by a finite secret value. The attacker attempts to gain access to this asset by using trial-and-error to exhaustively explore all the possible secret values in the hope of finding the secret (or a value that is functionally equivalent) that will unlock the asset.
  • Protocol Analysis CAPEC-192 An adversary engages in activities to decipher and/or decode protocol information for a network or application communication protocol used for transmitting information between interconnected nodes or systems on a packet-switched data network. While this type of analysis involves the analysis of a networking protocol inherently, it does not require the presence of an actual or physical network.
  • Encryption Brute Forcing CAPEC-20 An attacker, armed with the cipher text and the encryption algorithm used, performs an exhaustive (brute force) search on the key space to determine the key that decrypts the cipher text to obtain the plaintext.

Vulnerable Configurations

  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.1:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.1:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.2:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.2:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.3:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.3:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.8:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.4.8:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:-:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:-:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta3:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta3:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta4:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta4:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta6:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.0:beta6:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.1:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.1:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.2:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.5.2:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:-:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:-:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha4:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha5:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.6.0:alpha5:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:-:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:-:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha4:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha5:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha5:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha6:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha6:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha7:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha7:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha8:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha8:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha9:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.0:alpha9:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.1:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.1:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.2:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.2:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.3:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.3:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.4:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.4:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.5:*:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.7.5:*:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha10:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha10:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha11:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha11:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha12:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha12:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha13:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha13:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha14:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha14:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha15:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha15:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha16:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha16:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha17:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha17:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha18:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha18:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha19:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha19:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha20:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha20:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha21:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha21:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha22:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha22:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha23:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha23:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha24:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha24:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha25:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha25:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha26:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha26:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha27:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha27:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha28:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha28:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha29:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha29:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha30:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha30:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha31:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha31:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha32:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha32:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha33:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha33:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha34:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha34:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha35:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha35:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha36:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha36:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha37:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha37:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha38:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha38:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha4:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha5:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha5:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha6:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha6:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha7:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha7:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha8:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha8:*:*:*:*:*:*
  • cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha9:*:*:*:*:*:*
    cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha9:*:*:*:*:*:*

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