CVE-2026-53218
netfilter: nft_exthdr: fix register tracking for F_PRESENT flag
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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.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://git.kernel.org/stable/c/8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6
- https://git.kernel.org/stable/c/19748967d59c31d24d21d40b728570788310b237
- https://git.kernel.org/stable/c/46fc15a044e9938e7ea77786fb37edd2cd74f031
- https://git.kernel.org/stable/c/cd513e43b4b2bd1de39e2367bc4261c699a8652f
- https://git.kernel.org/stable/c/67b27434c43b68a97becda98c9f0c8cf6cba2134
References (11)
CVSS
- Attack Vector
- LOCAL
- Complexity
- LOW
- Privileges
- LOW
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- NONE
- Integrity
- NONE
- Availability
- HIGH
Quick Info
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