Medium severity4.4NVD Advisory· Published May 26, 2021· Updated Jun 17, 2026
CVE-2021-20177
CVE-2021-20177
Description
A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the system. Kernel before kernel 5.5-rc1 is affected.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
106- Linux/Linux kerneldescription
- osv-coords103 versionspkg:rpm/suse/kernel-rt&distro=SUSE%20Linux%20Enterprise%20Real%20Time%2012%20SP5pkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP1pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/kernel-source&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/kernel-default&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/kernel-livepatch-SLE15-SP1_Update_22&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP1pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-zfcpdump&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/kernel-default&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/kernel-syms&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/kernel-source&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/kernel-syms&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/kernel-docs&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-source&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-default&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/kernel-docs&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/kernel-syms&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/kernel-source-azure&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-azure&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-source-azure&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-syms-azure&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2012%20SP5pkg:rpm/suse/kgraft-patch-SLE12-SP5_Update_15&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2012%20SP5pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/kernel-default-base&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP2pkg:rpm/suse/kernel-preempt&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP2pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP2pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Legacy%2015%20SP2pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP2pkg:rpm/suse/kernel-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP2pkg:rpm/suse/kernel-rt_debug&distro=SUSE%20Real%20Time%20Module%2015%20SP2pkg:rpm/suse/kernel-source-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP2pkg:rpm/suse/kernel-rt_debug&distro=SUSE%20Linux%20Enterprise%20Real%20Time%2012%20SP5pkg:rpm/suse/kernel-syms-rt&distro=SUSE%20Linux%20Enterprise%20Real%20Time%2012%20SP5pkg:rpm/suse/kernel-source-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP2pkg:rpm/suse/kernel-syms-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP2pkg:rpm/suse/kernel-syms-azure&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2012%20SP5pkg:rpm/suse/kernel-preempt&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/kernel-livepatch-SLE15-SP2_Update_10&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP2pkg:rpm/suse/kernel-syms-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP2pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-docs&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/kernel-syms&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-zfcpdump&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2012%20SP5pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP2pkg:rpm/suse/kernel-source-rt&distro=SUSE%20Linux%20Enterprise%20Real%20Time%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP1pkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/kernel-docs&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/kernel-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP2pkg:rpm/suse/kernel-azure&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP2pkg:rpm/opensuse/kernel-debug&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-default-base&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-docs&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-kvmsmall&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-source&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-syms&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-obs-build&distro=openSUSE%20Leap%2015.2pkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP2pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP2pkg:rpm/suse/kernel-default&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/kernel-source&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/opensuse/kernel-default&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-obs-qa&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/kernel-preempt&distro=openSUSE%20Leap%2015.2
< 4.12.14-10.31.1+ 102 more
- (no CPE)range: < 4.12.14-10.31.1
- (no CPE)range: < 4.12.14-122.60.2
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 1-3.5.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 1-8.3.1
- (no CPE)range: < 4.12.14-122.60.1
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- (no CPE)range: < 5.3.18-24.49.2.9.21.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-25.1
- (no CPE)range: < 5.3.18-25.1
- (no CPE)range: < 5.3.18-25.1
- (no CPE)range: < 4.12.14-10.31.1
- (no CPE)range: < 4.12.14-10.31.1
- (no CPE)range: < 5.3.18-18.35.2
- (no CPE)range: < 5.3.18-18.35.2
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 1-5.3.2
- (no CPE)range: < 5.3.18-25.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
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- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-122.60.1
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 4.12.14-10.31.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-18.35.2
- (no CPE)range: < 4.12.14-16.44.1
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1.lp152.8.21.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-24.49.3
- (no CPE)range: < 5.3.18-24.49.2
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 4.12.14-197.83.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
- (no CPE)range: < 5.3.18-lp152.63.1
Patches
Vulnerability mechanics
References
1- bugzilla.redhat.com/show_bug.cginvdIssue TrackingPatchThird Party Advisory
News mentions
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