NVD Vulnerability Detail

CVE-2021-3492

Summary	Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.
Publication Date	April 17, 2021, 2:15 p.m.
Registration Date	April 17, 2021, 8:01 p.m.
Last Update	Nov. 21, 2024, 3:21 p.m.

Affected software configurations

Configuration1	or higher	or less	more than	less than
cpe:2.3:o:canonical:ubuntu_linux:::::lts:::*	18.04.1			20.04
cpe:2.3:o:canonical:ubuntu_linux:::::lts:::*				18.04

Configuration2		or higher	or less	more than	less than
cpe:2.3:o:canonical:ubuntu_linux:::::-:::*					20.10

Related information, measures and tools

No	URL	タグ
1	http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html	Third Party Advisory VDB Entry
2	http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html	Third Party Advisory VDB Entry
3	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333	Mailing List Patch Vendor Advisory
4	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333	Mailing List Patch Vendor Advisory
5	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6	Mailing List Patch Vendor Advisory
6	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6	Mailing List Patch Vendor Advisory
7	https://ubuntu.com/security/notices/USN-4917-1	Vendor Advisory
8	https://ubuntu.com/security/notices/USN-4917-1	Vendor Advisory
9	https://www.openwall.com/lists/oss-security/2021/04/16/2	Mailing List Third Party Advisory
10	https://www.openwall.com/lists/oss-security/2021/04/16/2	Mailing List Third Party Advisory
11	https://www.zerodayinitiative.com/advisories/ZDI-21-422/	Third Party Advisory VDB Entry
12	https://www.zerodayinitiative.com/advisories/ZDI-21-422/	Third Party Advisory VDB Entry

Common Vulnerabilities List

No	CWE	Name	URL
1	CWE-415	二重解放	https://cwe.mitre.org/data/definitions/415.html
2	CWE-401	有効期限後のメモリの解放の欠如	https://cwe.mitre.org/data/definitions/401.html

JVN Vulnerability Information

Ubuntu Linux Kernel における有効期限後のメモリの解放の欠如に関する脆弱性

Title	Ubuntu Linux Kernel における有効期限後のメモリの解放の欠如に関する脆弱性
Summary	Ubuntu Linux Kernel には、有効期限後のメモリの解放の欠如に関する脆弱性、および二重解放に関する脆弱性が存在します。 Zero Day Initiative は、本脆弱性に ZDI-CAN-13562 を採番していました。
Possible impacts	情報を取得される、情報を改ざんされる、およびサービス運用妨害 (DoS) 状態にされる可能性があります。
Solution	ベンダより正式な対策が公開されています。ベンダ情報を参照して適切な対策を実施してください。
Publication Date	April 12, 2021, midnight
Registration Date	Dec. 17, 2021, 12:15 p.m.
Last Update	Dec. 17, 2021, 12:15 p.m.

Affected System

Canonical

Ubuntu

CVE (情報セキュリティ共通脆弱性識別子)

No	Name	URL
Common Vulnerabilities and Exposures (CVE)
1	CVE-2021-3492	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3492
National Vulnerability Database (NVD)
2	CVE-2021-3492	https://nvd.nist.gov/vuln/detail/CVE-2021-3492

CWE (共通脆弱性タイプ一覧)

No	Name	URL
JVNDB
1	CWE-401	https://cwe.mitre.org/data/definitions/401.html
2	CWE-415	https://cwe.mitre.org/data/definitions/415.html

ベンダー情報

No	Name	URL
Launchpad
1	UBUNTU: SAUCE: shiftfs: free allocated memory in shiftfs_btrfs_ioctl_fd_replace() error paths	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6
2	UBUNTU: SAUCE: shiftfs: handle copy_to_user() return values correctly	https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333
Ubuntu Security Notice
3	USN-4917-1	https://ubuntu.com/security/notices/USN-4917-1

その他

No	Name	URL
関連文書
1	ZDI-21-422 ((Pwn2Own) Canonical Ubuntu ShiftFS File System Double Free Privilege Escalation Vulnerability)	https://www.zerodayinitiative.com/advisories/ZDI-21-422/

Change Log

No	Changed Details	Date of change
1	[2021年12月17日] 掲載	Dec. 17, 2021, 12:15 p.m.