GHSA-hggm-jpg3-v476 CVE-2020-25659 PYSEC-2021-62
RSA decryption vulnerable to Bleichenbacher timing vulnerability
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 2.46%
- Chance of exploitation in the next 30 days. Higher than 84.47% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-385 Covert Timing Channel
- Fix
3.2- Upgrade cryptography to this version or later
Description
RSA decryption was vulnerable to Bleichenbacher timing vulnerabilities, which would impact people using RSA decryption in online scenarios. This is fixed in cryptography 3.2.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| cryptography | < 3.2 |
3.2 |
| cryptography | < 3.2.1 |
3.2.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
cryptography PyPI → 3.2
- pip
pip install --upgrade "cryptography>=3.2"- poetry
poetry add "cryptography>=3.2"- uv
uv add "cryptography>=3.2"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 5.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-385: Covert Timing Channel
Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.
How to prevent it
- Architecture and Design: Whenever possible, specify implementation strategies that do not introduce time variances in operations.
- Implementation: Often one can artificially manipulate the time which operations take or -- when operations occur -- can remove information from the attacker.
- Implementation: It is reasonable to add artificial or random delays so that the amount of CPU time consumed is independent of the action being taken by the application.
References
Advisories
Packages
Other links
- github.com/pyca/cryptography/security/advisories/GHSA-hggm-jpg3-v476
- github.com/pyca/cryptography/pull/5507
- github.com/pyca/cryptography/commit/58494b41d6ecb0f56b7c5f05d5f5e3ca0320d494
- github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2021-62.yaml
- pypi.org/project/cryptography
- oracle.com/security-alerts/cpuapr2022.html
- oracle.com/security-alerts/cpujul2022.html
- github.com/pyca/cryptography/pull/5507/commits/ce1bef6f1ee06ac497ca0c837fbd1c7e…
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-m2h6-j472-rp4c python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees | Medium | Also affects cryptography |
| GHSA-jwv3-5hgf-82ww python-cryptography: Duplicate self-signed intermediates can cause exponential path-building | High | Also affects cryptography |
| GHSA-g6cj-pr64-35w5 cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing | High | Also affects cryptography |
| GHSA-537c-gmf6-5ccf Vulnerable OpenSSL included in cryptography wheels | High | Also affects cryptography |
| GHSA-p423-j2cm-9vmq Cryptography vulnerable to buffer overflow if non-contiguous buffers were passed to APIs | Medium | Also affects cryptography |
| GHSA-m959-cc7f-wv43 cryptography has incomplete DNS name constraint enforcement on peer names | Low | Also affects cryptography |
| GHSA-r6ph-v2qm-q3c2 cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves | High | Also affects cryptography |
| GHSA-79v4-65xg-pq4g Vulnerable OpenSSL included in cryptography wheels | Medium | Also affects cryptography |
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