CVE-2021-43535
説明
The Mozilla Foundation Security Advisory describes this flaw as:
A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash.
CVSS (Common Vulnerability Scoring System) のスコアの詳細
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 スコアの内訳
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| ベーススコア | 8.8 | 8.8 | N/A |
| 攻撃ベクトル | Network | Network | N/A |
| 攻撃の複雑さ | Low | Low | N/A |
| 必要な権限 | None | None | N/A |
| ユーザー関与レベル | Required | Required | N/A |
| 範囲 | Unchanged | Unchanged | N/A |
| 機密性 | High | High | N/A |
| 完全性への影響 | High | High | N/A |
| 可用性への影響 | High | High | N/A |
ベクトル
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
脆弱性の原因 (CWE) の理解
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
よくある質問
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