Vulnerability Name:

CVE-2020-29534 (CCN-192618)

Assigned:2020-09-12
Published:2020-09-12
Updated:2021-06-02
Summary:An issue was discovered in the Linux kernel before 5.9.3. io_uring takes a non-refcounted reference to the files_struct of the process that submitted a request, causing execve() to incorrectly optimize unshare_fd(), aka CID-0f2122045b94.
CVSS v3 Severity:7.8 High (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
7.0 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
6.2 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
5.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): None
Availibility (A): None
CVSS v2 Severity:7.2 High (CVSS v2 Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Complete
Integrity (I): Complete
Availibility (A): Complete
4.9 Medium (CCN CVSS v2 Vector: AV:L/AC:L/Au:N/C:C/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): Complete
Integrity (I): None
Availibility (A): None
Vulnerability Type:CWE-Other
Vulnerability Consequences:Obtain Information
References:Source: MITRE
Type: CNA
CVE-2020-29534

Source: MISC
Type: Exploit, Issue Tracking, Patch, Third Party Advisory
https://bugs.chromium.org/p/project-zero/issues/detail?id=2089

Source: CCN
Type: Google Security Research Issue 2089
Linux: io_uring: ->mm and ->files access across suid boundaries

Source: MISC
Type: Patch, Vendor Advisory
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9.3

Source: XF
Type: UNKNOWN
linux-kernel-cve202029534-info-disc(192618)

Source: CCN
Type: Linux Kernel GIT Repository
io_uring: don't rely on weak ->files references

Source: MISC
Type: Patch, Vendor Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f2122045b946241a9e549c2a76cea54fa58a7ff

Source: CCN
Type: Packet Storm Security [12-07-2020]
inux io_uring SUID Boundary Access Violation

Vulnerable Configuration:Configuration 1:
  • cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 5.1 and < 5.8.18)
  • OR cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 5.9.0 and < 5.9.3)
  • OR cpe:/o:linux:linux_kernel:5.10:rc1:*:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/o:linux:linux_kernel:5.9:rc1:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    linux linux kernel *
    linux linux kernel *
    linux linux kernel 5.10 rc1
    linux linux kernel 5.9 rc1