CVE-2026-53218
Last modified
CVE-2026-53218 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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). EPSS estimates a 0.18% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | >= 4.11, < 5.10.259 | — |
| Linux | Linux Kernel | >= 5.11, < 5.15.210 | — |
| Linux | Linux Kernel | >= 5.16, < 6.1.176 | — |
| Linux | Linux Kernel | >= 6.2, < 6.6.143 | — |
| Linux | Linux Kernel | >= 6.7, < 6.12.94 | — |
| Linux | Linux Kernel | >= 6.13, < 6.18.36 | — |
| Linux | Linux Kernel | >= 6.19, < 7.0.13 | — |
| Linux | Linux Kernel | 7.1 | Rc1 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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