{"id":"CVE-2021-22555","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-22555","generatedAt":"2026-10-27T20:22:08.613Z","title":"Linux Kernel Heap Out-of-Bounds Write Vulnerability","description":"A heap out-of-bounds write affecting Linux since v2.6.19-rc1 was discovered in net/netfilter/x_tables.c. This allows an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space","published":"2021-07-07T12:15:08.000Z","lastModified":"2026-10-13T18:25:34.000Z","status":"Analyzed","sourceIdentifier":"cve-coordination@google.com","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-787"],"affected":["netapp/c400 firmware","netapp/c250 firmware","netapp/h410c firmware","netapp/h300s firmware","netapp/h500s firmware","netapp/h700s firmware","netapp/h410s firmware","linux/linux kernel","broadcom/fabric operating system","netapp/fas 8300 firmware","netapp/fas 8700 firmware","netapp/aff a400 firmware","netapp/aff a250 firmware","netapp/aff 500f firmware","netapp/h610c firmware","netapp/h610s firmware","netapp/h615c firmware","netapp/cloud backup","netapp/hci management node","netapp/solidfire","netapp/solidfire baseboard management controller"],"epss":{"score":0.78684,"percentile":0.99585,"date":"2026-10-26","history":[]},"kev":{"listed":true,"dateAdded":"2025-10-06","dueDate":"2025-10-27","knownRansomwareCampaignUse":"Unknown","notes":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\nhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 ; https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d ; https://security.netapp.com/advisory/ntap-20210805-0010/ ; https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 ; https://nvd.nist.gov/vuln/detail/CVE-2021-22555"},"exploits":{"count":1,"verified":true,"firstPublished":"2021-07-15","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":50135,"kind":"exploit","title":"Linux Kernel 2.6.19 < 5.9 - 'Netfilter Local Privilege Escalation","url":"https://www.exploit-db.com/exploits/50135","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/local/50135.c","file":"exploits/linux/local/50135.c","published":"2021-07-15","added":"2021-07-16","updated":"2021-11-17","author":"TheFloW","type":"local","platform":"linux","port":null,"verified":true,"codes":["CVE-2021-22555"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":"https://github.com/google/security-research/blob/d4d6a96c9c8b00929559a84f3d7560903b6413c2/pocs/linux/cve-2021-22555/exploit.c"}]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 27 October 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html","tags":["Third Party Advisory","VDB Entry"],"source":"cve-coordination@google.com"},{"url":"http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve-coordination@google.com"},{"url":"http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve-coordination@google.com"},{"url":"http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve-coordination@google.com"},{"url":"http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve-coordination@google.com"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21","tags":["Mailing List","Patch","Vendor Advisory"],"source":"cve-coordination@google.com"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d","tags":["Mailing List","Patch","Vendor Advisory"],"source":"cve-coordination@google.com"},{"url":"https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528","tags":["Exploit","Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"https://security.netapp.com/advisory/ntap-20210805-0010/","tags":["Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21","tags":["Mailing List","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d","tags":["Mailing List","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210805-0010/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22555","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-22555","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}