CVE-2021-22898
Description
A flaw was found in the way curl handled telnet protocol option for sending environment variables, which could lead to sending of uninitialized data from a stack-based buffer to the server. This issue leads to potentially revealing sensitive internal information to the server using a clear-text network protocol.
Mitigation
This issue can be avoided by not setting any telnet options for the curl command line tool (using the -t / --telnet-option command line option) or the libcurl library (using the CURLOPT_TELNETOPTIONS option) when telnet protocol is not meant to be used.
If telnet protocol needs to be used with curl / libcurl, along with the NEW_ENV telnet option, ensure that no environment variable set via the NEW_ENV option has the name or value longer than 127 bytes.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.1 | 3.1 | 3.1 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | High | High |
| Privileges Required | None | None | None |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | Low | Low |
| Integrity Impact | None | None | None |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory; Read Application Data
When reusing a resource such as memory or a program variable, the original contents of that resource may not be cleared before it is sent to an untrusted party.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend.
Acknowledgements
Red Hat would like to thank the Curl Project for reporting this issue. Upstream acknowledges Harry Sintonen as the original reporter.
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