CVE-2021-22555
Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE
02 Description
Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE
03 Exploitation and scoring
- Exploitation
- Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2025-10-06. Federal remediation due 2025-10-27.
- SSVC decision
- ExploitationactiveCISA reports credible evidence of active exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 78.68% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 99.5% of scored records. A rank, not a probability.
- NVD base score
- 7.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-10-13.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-07-07 11:20Z5 YR AGO
- Last updated
- 2025-12-30 20:32Z10 MO AGO
- Reserved
- 2021-01-05
- Assigning CNA
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.3)
- CNA CVSS vector
- CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- Weaknesses
- CWE-787Out-of-bounds WriteBase
- Data version
- 5.2
- Document digest
- e091febae3b7cfe556d6635d0c800023b91c7f32cac127cbddd9bef6fe28911b
05 Affected products
06 References
- github.comhttps://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528
- git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21
- git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d
- packetstormsecurity.comhttp://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20210805-0010/
- packetstormsecurity.comhttp://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html
- www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22555
07 Fixed in
AlmaLinux 8
- kernel-tools-libs-devel Fixed in 4.18.0-305.12.1.el8_4
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Arch Linux
- linux Fixed in 5.11.15.arch1-2
- linux-hardened Fixed in 5.11.15.hardened1-1
- linux-lts Fixed in 5.10.31-1
- linux-zen Fixed in 5.11.15.zen1-2
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
CloudLinux 8
- kernel-tools-libs-devel Fixed in 4.18.0-305.12.1.el8_4
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- linux Fixed in 5.10.38-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- linux Fixed in 5.10.38-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- linux Fixed in 5.10.38-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- linux-hwe-edge No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- linux Fixed in 4.15.0-144.148
- linux-aws Fixed in 4.15.0-1103.110
- linux-aws-5.0 No fix yet
- linux-aws-5.3 No fix yet
- linux-aws-5.4 Fixed in 5.4.0-1049.51~18.04.1
- linux-azure No fix yet
- linux-azure-4.15 Fixed in 4.15.0-1115.128
- linux-azure-5.3 No fix yet
- linux-azure-5.4 Fixed in 5.4.0-1048.50~18.04.1
- linux-azure-edge No fix yet
- linux-dell300x Fixed in 4.15.0-1022.26
- linux-gcp No fix yet
- linux-gcp-4.15 Fixed in 4.15.0-1100.113
- linux-gcp-5.3 No fix yet
- linux-gcp-5.4 Fixed in 5.4.0-1044.47~18.04.2
- linux-gcp-edge No fix yet
- linux-gke-4.15 No fix yet
- linux-gke-5.4 Fixed in 5.4.0-1044.46~18.04.1
- linux-gkeop-5.4 Fixed in 5.4.0-1016.17~18.04.1
- linux-hwe No fix yet
- linux-hwe-5.4 Fixed in 5.4.0-74.83~18.04.1
- linux-hwe-edge No fix yet
- linux-kvm Fixed in 4.15.0-1092.94
- linux-oem No fix yet
- linux-oracle Fixed in 4.15.0-1072.80
- linux-oracle-5.0 No fix yet
- linux-oracle-5.3 No fix yet
- linux-oracle-5.4 Fixed in 5.4.0-1046.50~18.04.2
- linux-raspi-5.4 Fixed in 5.4.0-1036.39~18.04.1
- linux-raspi2 Fixed in 4.15.0-1086.91
- linux-snapdragon Fixed in 4.15.0-1103.112
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- linux Fixed in 5.4.0-74.83
- linux-aws Fixed in 5.4.0-1049.51
- linux-azure Fixed in 5.4.0-1048.50
- linux-bluefield Fixed in 5.4.0-1012.15
- linux-gcp Fixed in 5.4.0-1044.47
- linux-gke Fixed in 5.4.0-1044.46
- linux-gkeop Fixed in 5.4.0-1016.17
- linux-hwe-5.8 Fixed in 5.8.0-55.62~20.04.1
- linux-kvm Fixed in 5.4.0-1040.41
- linux-oem-5.10 Fixed in 5.10.0-1025.26
- linux-oem-5.6 No fix yet
- linux-oracle Fixed in 5.4.0-1046.50
- linux-raspi Fixed in 5.4.0-1036.39
- linux-raspi2 No fix yet
- linux-riscv No fix yet
- linux-riscv-5.8 Fixed in 5.8.0-26.28~20.04.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- linux-intel-iot-realtime No fix yet
- linux-realtime No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- linux-raspi-realtime No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- linux Fixed in 3.13.0-187.238Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-aws Fixed in 4.4.0-1095.100Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-azure Fixed in 4.15.0-1115.128~14.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-lts-xenial Fixed in 4.4.0-213.245~14.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- linux Fixed in 4.4.0-213.245Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-aws Fixed in 4.4.0-1131.145Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-aws-hwe Fixed in 4.15.0-1103.110~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-azure Fixed in 4.15.0-1115.128~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-gcp Fixed in 4.15.0-1100.113~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-hwe Fixed in 4.15.0-144.148~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-kvm Fixed in 4.4.0-1096.105Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-oracle Fixed in 4.15.0-1072.80~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 16.04 LTS
- linux-fips Fixed in 4.4.0-1065.71Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 18.04 LTS
- linux-aws-fips Fixed in 4.15.0-2045.47Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-azure-fips Fixed in 4.15.0-2027.30Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-fips Fixed in 4.15.0-1060.68Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 20.04 LTS
- linux-aws-fips Fixed in 5.4.0-1069.73+fips2Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-azure-fips Fixed in 5.4.0-1073.76+fips1Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-gcp-fips Fixed in 5.4.0-1067.71~20.04.1Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 16.04 LTS
- linux-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 18.04 LTS
- linux-aws-fips No fix yet
- linux-azure-fips No fix yet
- linux-fips No fix yet
- linux-gcp-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 20.04 LTS
- linux-aws-fips No fix yet
- linux-azure-fips No fix yet
- linux-fips No fix yet
- linux-gcp-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.