CVE-2026-53218
netfilter: nft_exthdr: fix register tracking for F_PRESENT flag
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_exthdr: fix register tracking for F_PRESENT flag nft_exthdr_init() passes user-controlled priv->len to nft_parse_register_store(), which marks that many bytes in the register bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT is set, the eval paths write only 1 byte (nft_reg_store8) or 4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4, registers beyond the first are never written, retaining uninitialized stack data from nft_regs. Bail out if userspace requests too much data when F_PRESENT is set.
INFO
Published Date :
June 25, 2026, 9:16 a.m.
Last Modified :
July 2, 2026, 8:52 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to incorporate the fix.
- Validate user-controlled length against F_PRESENT flag.
- Ensure registers are properly initialized before use.
- Bail out if userspace requests too much data.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-53218.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-53218 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-53218
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-53218 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-53218 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 02, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-908 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc7:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.11 up to (excluding) 5.10.259 Added Reference Type kernel.org: https://git.kernel.org/stable/c/19748967d59c31d24d21d40b728570788310b237 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/46fc15a044e9938e7ea77786fb37edd2cd74f031 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/67b27434c43b68a97becda98c9f0c8cf6cba2134 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/772cecf198da732faebb5dcfc46d66a505be8495 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/78069a6d8bc86c9e036eb82c2af4a19cc1871a53 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/cd513e43b4b2bd1de39e2367bc4261c699a8652f Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265 Types: Patch -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '19748967d59c31d24d21d40b728570788310b237', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '46fc15a044e9938e7ea77786fb37edd2cd74f031', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': 'cd513e43b4b2bd1de39e2367bc4261c699a8652f', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '67b27434c43b68a97becda98c9f0c8cf6cba2134', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '78069a6d8bc86c9e036eb82c2af4a19cc1871a53', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': 'f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265', 'versionType': 'git'}, {'status': 'affected', 'version': 'c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783', 'lessThan': '772cecf198da732faebb5dcfc46d66a505be8495', 'versionType': 'git'}], 'programFiles': ['net/netfilter/nft_exthdr.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/netfilter/nft_exthdr.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_exthdr: fix register tracking for F_PRESENT flag nft_exthdr_init() passes user-controlled priv->len to nft_parse_register_store(), which marks that many bytes in the register bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT is set, the eval paths write only 1 byte (nft_reg_store8) or 4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4, registers beyond the first are never written, retaining uninitialized stack data from nft_regs. Bail out if userspace requests too much data when F_PRESENT is set. Added Reference https://git.kernel.org/stable/c/19748967d59c31d24d21d40b728570788310b237 Added Reference https://git.kernel.org/stable/c/46fc15a044e9938e7ea77786fb37edd2cd74f031 Added Reference https://git.kernel.org/stable/c/67b27434c43b68a97becda98c9f0c8cf6cba2134 Added Reference https://git.kernel.org/stable/c/772cecf198da732faebb5dcfc46d66a505be8495 Added Reference https://git.kernel.org/stable/c/78069a6d8bc86c9e036eb82c2af4a19cc1871a53 Added Reference https://git.kernel.org/stable/c/8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6 Added Reference https://git.kernel.org/stable/c/cd513e43b4b2bd1de39e2367bc4261c699a8652f Added Reference https://git.kernel.org/stable/c/f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265