Observable discrepancy in Linux kernel

1) Observable discrepancy

EUVDB-ID: #VU92753

Risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38209

CWE-ID: CWE-203 - Observable discrepancy

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

net/netfilter/nf_conntrack_standalone.c in the Linux kernel before 5.12.2 allows observation of changes in any net namespace because these changes are leaked into all other net namespaces. This is related to the NF_SYSCTL_CT_MAX, NF_SYSCTL_CT_EXPECT_MAX, and NF_SYSCTL_CT_BUCKETS sysctls.

Mitigation

Install update from vendor's repository.

Vulnerable software versions

Linux kernel: All versions

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:*:*:*:*:*:*:*:*

External links

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.2
https://github.com/torvalds/linux/commit/2671fa4dc0109d3fb581bc3078fdf17b5d9080f6

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.