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CVE-2020-26263 Detail

Description

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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/tlsfuzzer/tlslite-ng/commit/c28d6d387bba59d8bd5cb3ba15edc42edf54b368 Patch  Third Party Advisory 
https://github.com/tlsfuzzer/tlslite-ng/pull/438 Patch  Third Party Advisory 
https://github.com/tlsfuzzer/tlslite-ng/pull/439 Patch  Third Party Advisory 
https://github.com/tlsfuzzer/tlslite-ng/security/advisories/GHSA-wvcv-832q-fjg7 Exploit  Patch  Third Party Advisory 
https://pypi.org/project/tlslite-ng/ Product  Third Party Advisory 
https://securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/ Exploit  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-326 Inadequate Encryption Strength GitHub, Inc.  

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-26263
NVD Published Date:
12/21/2020
NVD Last Modified:
12/23/2020
Source:
GitHub, Inc.