CVE-2020-26263
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
tlslite-ngPyPI | < 0.7.6 | 0.7.6 |
Affected products
41cpe:2.3:a:tlslite-ng_project:tlslite-ng:*:*:*:*:*:*:*:*+ 38 more
- cpe:2.3:a:tlslite-ng_project:tlslite-ng:*:*:*:*:*:*:*:*range: <0.7.6
- 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: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: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: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: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:alpha1:*:*:*:*:*:*
- 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: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: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: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: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:alpha2:*:*:*:*:*:*
- 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: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: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: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:alpha38:*:*:*:*:*:*
- 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: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: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:alpha8:*:*:*:*:*:*
- cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha9:*:*:*:*:*:*
- Range: < 0.7.6
Patches
Vulnerability mechanics
References
11- github.com/tlsfuzzer/tlslite-ng/commit/c28d6d387bba59d8bd5cb3ba15edc42edf54b368nvdPatchThird Party AdvisoryWEB
- github.com/tlsfuzzer/tlslite-ng/pull/438nvdPatchThird Party AdvisoryWEB
- github.com/tlsfuzzer/tlslite-ng/pull/439nvdPatchThird Party AdvisoryWEB
- github.com/tlsfuzzer/tlslite-ng/security/advisories/GHSA-wvcv-832q-fjg7nvdExploitPatchThird Party AdvisoryWEB
- securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/nvdExploitThird Party Advisory
- github.com/advisories/GHSA-wvcv-832q-fjg7ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2020-26263ghsaADVISORY
- pypi.org/project/tlslite-ng/nvdProductThird Party Advisory
- github.com/pypa/advisory-database/tree/main/vulns/tlslite-ng/PYSEC-2020-143.yamlghsaWEB
- pypi.org/project/tlslite-ngghsaWEB
- securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-pythonghsaWEB
News mentions
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