CVE-2020-10878
Description
From CVE.org
Perl before 5.30.3 has an integer overflow related to mishandling of a "PL_regkind[OP(n)] == NOTHING" situation. A crafted regular expression could lead to malformed bytecode with a possibility of instruction injection.
Statement
This flaw is an integer overflow triggered when an application compiles a specially crafted, untrusted regular expression pattern supplied by a user, as most applications match untrusted data against a trusted regex pattern.The flaw leads to a corruption of the intermediate language state. While this could theoretically allow an attacker to insert instructions, the resulting behavior is unpredictable, and any potential code execution is likely outside of an attacker's reliable control. Therefore, the most probable and practical impact is an application crash, resulting in a Denial of Service (DoS).
Mitigation
To mitigate this flaw, developers should not allow untrusted regular expressions to be compiled by the Perl regular expression compiler.
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 | 8.6 | 8.6 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Red Hat CVSS v3 Score Explanation
C:L and I:L because in order to exploit this flaw, the application must already evaluate regular expressions supplied by an attacker. This would also likely not lead to compromise of the entire application data's confidentiality and integrity.
Acknowledgements
Red Hat would like to thank Hugo van der Sanden and Slaven Rezic for reporting this issue.
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