Linux Distros Unpatched Vulnerability : CVE-2021-47129

medium Nessus Plugin ID 245247

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: skip expectations for confirmed conntrack nft_ct_expect_obj_eval() calls nf_ct_ext_add() for a confirmed conntrack entry.
However, nf_ct_ext_add() can only be called for !nf_ct_is_confirmed(). [ 1825.349056] WARNING: CPU: 0 PID:
1279 at net/netfilter/nf_conntrack_extend.c:48 nf_ct_xt_add+0x18e/0x1a0 [nf_conntrack] [ 1825.351391] RIP:
0010:nf_ct_ext_add+0x18e/0x1a0 [nf_conntrack] [ 1825.351493] Code: 41 5c 41 5d 41 5e 41 5f c3 41 bc 0a 00 00 00 e9 15 ff ff ff ba 09 00 00 00 31 f6 4c 89 ff e8 69 6c 3d e9 eb 96 45 31 ed eb cd <0f> 0b e9 b1 fe ff ff e8 86 79 14 e9 eb bf 0f 1f 40 00 0f 1f 44 00 [ 1825.351721] RSP: 0018:ffffc90002e1f1e8 EFLAGS: 00010202 [ 1825.351790] RAX: 000000000000000e RBX: ffff88814f5783c0 RCX: ffffffffc0e4f887 [ 1825.351881] RDX:
dffffc0000000000 RSI: 0000000000000008 RDI: ffff88814f578440 [ 1825.351971] RBP: 0000000000000000 R08:
0000000000000000 R09: ffff88814f578447 [ 1825.352060] R10: ffffed1029eaf088 R11: 0000000000000001 R12:
ffff88814f578440 [ 1825.352150] R13: ffff8882053f3a00 R14: 0000000000000000 R15: 0000000000000a20 [ 1825.352240] FS: 00007f992261c900(0000) GS:ffff889faec00000(0000) knlGS:0000000000000000 [ 1825.352343] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1825.352417] CR2: 000056070a4d1158 CR3:
000000015efe0000 CR4: 0000000000350ee0 [ 1825.352508] Call Trace: [ 1825.352544] nf_ct_helper_ext_add+0x10/0x60 [nf_conntrack] [ 1825.352641] nft_ct_expect_obj_eval+0x1b8/0x1e0 [nft_ct] [ 1825.352716] nft_do_chain+0x232/0x850 [nf_tables] Add the ct helper extension only for unconfirmed conntrack. Skip rule evaluation if the ct helper extension does not exist. Thus, you can only create expectations from the first packet. It should be possible to remove this limitation by adding a new action to attach a generic ct helper to the first packet. Then, use this ct helper extension from follow up packets to create the ct expectation. While at it, add a missing check to skip the template conntrack too and remove check for IPCT_UNTRACK which is implicit to !ct. (CVE-2021-47129)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 245247

File Name: unpatched_CVE_2021_47129.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 8/7/2025

Updated: 8/7/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 4.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:P

CVSS Score Source: CVE-2021-47129

CVSS v3

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 4

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:linux-hwe, p-cpe:/a:canonical:ubuntu_linux:linux-intel-5.13, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-edge, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.11, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-riscv, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.17, p-cpe:/a:canonical:ubuntu_linux:linux-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-gke, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-azure, p-cpe:/a:canonical:ubuntu_linux:linux-raspi-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.2, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fips, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-oem, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-allwinner-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-azure-edge, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.0, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-aws-fips, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.10, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-fips, p-cpe:/a:canonical:ubuntu_linux:linux-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-fips, p-cpe:/a:canonical:ubuntu_linux:linux-intel-iot-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.19, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gke-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.6, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.1, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.13

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 1/28/2022

Reference Information

CVE: CVE-2021-47129

Detections

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