CVE-2026-53267
Description
A flaw was found in the Linux kernel's netfilter subsystem. A local attacker can exploit this vulnerability by creating specially crafted netfilter rules. This can lead to a memory corruption issue, where data on the kernel's memory stack is overwritten. Successful exploitation could result in information disclosure or potentially allow the attacker to gain elevated privileges.
Statement
nft_ct_get_eval() can treat a per CPU template conntrack object as a real conntrack entry after a rule first attaches a template ct and then reads ct original address fields from the same skb. In that state nf_ct_l3num(ct) can be 0 and the old code may take the 16 byte address copy path even when the destination register was validated for a shorter value. With dreg set near the end of struct nft_regs, this becomes an out of bounds write past the nft_regs area on the kernel stack. For the CVSS the PR:L is used because reliable triggering requires local ability to install crafted nftables rules, typically CAP_NET_ADMIN or delegated network administration in a namespace. Impact is at least local denial of service.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.6 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| Integrity Impact | Low | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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