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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47245netfilter: synproxy: Fix out of bounds when parsing TCP options

High 8.2

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 56% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.8%top 43.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: Fix out of bounds when parsing TCP options The TCP option parser in synproxy (synproxy_parse_options) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added an early return when length < 0 to avoid calling skb_header_pointer with negative length.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.46-1DEBIAN-CVE-2021-47245
Debian:13linux5.10.46-1DEBIAN-CVE-2021-47245
Debian:14linux5.10.46-1DEBIAN-CVE-2021-47245
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47245
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47245
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47245

Affected products (as reported)

VendorProductVersions
Linux Linux 48b1de4c110a7afa4b85862f6c75af817db26fad – before e1eb98cfeafdd85537e7e3cefe93ca9bfbcc3ea848b1de4c110a7afa4b85862f6c75af817db26fad – before 576c1526b4d83c44ad7b673cb841f36cbc6cb6c448b1de4c110a7afa4b85862f6c75af817db26fad – before 674b5f0c6a4fc5d3abce877048290cea6091fcb148b1de4c110a7afa4b85862f6c75af817db26fad – before 7d9a9a1a88a3da574e019b4de756bc73337b3b0b48b1de4c110a7afa4b85862f6c75af817db26fad – before 6defc77d48eff74075b80ad5925061b2fc010d9848b1de4c110a7afa4b85862f6c75af817db26fad – before 9cdf299ba4e153b5e56187648420de22c6216f0248b1de4c110a7afa4b85862f6c75af817db26fad – before f648089337cb8ed40b2bb96e244f72b9d97dc96b48b1de4c110a7afa4b85862f6c75af817db26fad – before 5fc177ab759418c9537433e63301096e733fb915
Linux Linux 3.12

References