GHSA-8ch4-58qp-g3mp CVE-2021-33880 PYSEC-2021-95
Observable Timing Discrepancy in aaugustin websockets library
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 2.27%
- Chance of exploitation in the next 30 days. Higher than 83.01% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
9.1- Upgrade websockets to this version or later
Description
The aaugustin websockets library before 9.1 for Python has an Observable Timing Discrepancy on servers when HTTP Basic Authentication is enabled with basic_auth_protocol_factory(credentials=...). An attacker may be able to guess a password via a timing attack.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| websockets | < 9.1 |
9.1 |
| websockets | < 9.1 |
9.1 |
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.
websockets PyPI → 9.1
- pip
pip install --upgrade "websockets>=9.1"- poetry
poetry add "websockets>=9.1"- uv
uv add "websockets>=9.1"
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-203: Observable Discrepancy
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
CWE-208: Observable Timing Discrepancy
Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
References
Advisories
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-6g87-ff9q-v847 websockets is vulnerable to denial of service by memory exhaustion | High | Also affects websockets |
| EEF-CVE-2026-65626 Bleichenbacher padding oracle in RSAES-PKCS1-v1_5 decryption in jose | Not rated yet | Same weakness, CWE-203 |
| GHSA-vwp5-f99x-x3rq Backstage has improper input validation in scaffolder task list ordering | Medium | Same weakness, CWE-203 |
| GHSA-v6q3-xqxm-6f5v Ghost: Invite Token Disclosure in Ghost Admin API | High | Same weakness, CWE-203 |
| GHSA-53vv-xm9f-mm82 Ghost: Password Hash Ordering Disclosure in Ghost Admin API | Low | Same weakness, CWE-203 |
| GHSA-2p9g-x3cv-5hh4 Private Weblate projects vulnerable to observable object existence disclosure via globally scoped object lookups | Medium | Same weakness, CWE-203 |
| GHSA-8fxq-53rx-ph5f Coder: Login endpoint user enumeration via timing-defense placeholder in password comparison | Medium | Same weakness, CWE-203 |
| GHSA-4pjg-x8qj-33j5 SiYuan: authFilePublishAccess distinguishes hidden and forbidden documents from public and nonexistent ones, and issues a publish-auth cookie for documents it reports as forbidden | Medium | Same weakness, CWE-203 |
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