CVE-2020-12723
Description
From CVE.org
regcomp.c in Perl before 5.30.3 allows a buffer overflow via a crafted regular expression because of recursive S_study_chunk calls.
Statement
A vulnerability in the Perl regular expression compiler affects Red Hat Enterprise Linux 7 and 8. The flaw exists in the S_study_chunk() function's handling of GOSUB opcodes during regular expression compilation. When processing untrusted regular expressions, recursive calls to S_study_chunk() can corrupt the intermediate language state, allowing an attacker to inject malicious instructions into the compiled regular expression. This network-accessible vulnerability can lead to denial of service. To mitigate, applications should not allow compilation of untrusted regular expressions. Note that this issue affects regular expression compilation, not pattern matching against untrusted input.
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 | 7.5 | 7.5 | 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 | None | None | N/A |
| Integrity Impact | None | None | 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:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability
Technical Impact: Execute Unauthorized Code or Commands
Acknowledgements
Red Hat would like to thank Sergey Aleynikov for reporting this issue.
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