PT-2021-2999 · Linux+3 · Linux Kernel+3

吴异 · Published 2021-01-12 · Updated 2024-08-03 · CVE-2021-3178

Positive Technologies (AI Summary)

CVSS v2.0

6.8

Medium

Base vector

AV:L/AC:L/Au:S/C:C/I:C/A:C

Name of the Vulnerable Software and Affected Versions Linux kernel versions through 5.10.8

Description The issue is related to the fs/nfsd/nfs3xdr.c component in the Linux kernel, which allows remote attackers to traverse to other parts of the filesystem via READDIRPLUS when there is an NFS export of a subdirectory of a filesystem. Some parties argue that such a subdirectory export is not intended to prevent this attack, and it is also related to the exports(5) no subtree check default behavior.

Recommendations For Linux kernel versions through 5.10.8, consider disabling the READDIRPLUS functionality as a temporary workaround until a patch is available. Restrict access to the vulnerable fs/nfsd/nfs3xdr.c component to minimize the risk of exploitation. Avoid using the NFS export of a subdirectory of a filesystem until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Path traversal

Use After Free

Weakness Enumeration

CWE-22

CWE-416

Related Identifiers

ALT-PU-2021-1089

ALT-PU-2021-1127

ALT-PU-2021-1188

ALT-PU-2021-1211

ALT-PU-2021-1417

ALT-PU-2021-1424

ALT-PU-2021-1446

ALT-PU-2021-1621

ALT-PU-2021-1656

ALT-PU-2021-1739

ALT-PU-2021-1862

ALT-PU-2021-1866

ALT-PU-2021-1870

BDU:2021-02592

BDU:2021-02593

CVE-2021-3178

DLA-2586-1

MGASA-2021-0058

MGASA-2021-0061

OESA-2021-1086

OESA-2021-1087

USN-4876-1

USN-4877-1

USN-4878-1

USN-4910-1

USN-4912-1

Affected Products

Alt Linux

Linuxmint

Linux Kernel

Ubuntu

References · 122

• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-3348 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2020-29568 · Security Note
• https://ubuntu.com/security/notices/USN-4912-1 · Vendor Advisory
• https://lists.fedoraproject.org/archives/list/[e-mail]/message/5SGB7TNDVQEOJ7NVTGX56UWHDNQM5TRC · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-20268 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2020-0444 · Security Note
• https://osv.dev/vulnerability/USN-4912-1 · Vendor Advisory
• https://advisories.mageia.org/MGASA-2021-0058.html · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2020-0423 · Security Note
• https://ubuntu.com/security/CVE-2021-20239 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-3347 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-3178 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2019-16089 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2021-3347 · Vendor Advisory