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CVE-2026-53266

8.8 HIGH 0.9% exploit odds exploited in the wild Fix listed Memory safety OS & kernel

What it is

In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: make ebt_snat ARP rewrite writable The ebtables SNAT target keeps the Ethernet source address rewrite behind skb_ensure_writable(skb, 0). This is intentional: at the bridge ebtables hooks the Ethernet header is addressed through skb_mac_header()/eth_hdr(), while skb->data points at the Ethernet payload. Asking skb_ensure_writable() for ETH_HLEN bytes would check the payload, not the Ethernet header, and would reintroduce the small packet regression fixed by commit 63137bc5882a. However, the optional ARP sender hardware address rewrite is different. It writes through skb_store_bits() at an offset relative to skb->data: skb_store_bits(skb, sizeof(struct arphdr), info->mac, ETH_ALEN) skb_header_pointer() only safely reads the ARP header; it does not make the later sender hardware address range writable. If that range is still held in a nonlinear skb fragment backed by a splice-imported file page, skb_store_bits() maps the frag page and copies the new MAC address directly into it. Ensure the ARP SHA range is writable before reading the ARP header and before calling skb_store_bits().

At a glance

Exploitability
Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
In the wild
CISA lists this as exploited in real attacks. Treat as urgent.
Fix
A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

  1. ReservedThe CVE id was reserved by its CNA
  2. PublishedDisclosed publicly on CVE.org and NVD
  3. 2026-09-18 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
  4. Last updatedMost recent change to the record
  5. 2026-09-21 Remediation deadlineCISA's due date for federal agencies to fix it

Why it ranks here

Details

Published
Last modified
Added to CISA KEV
2026-09-18
Exploit probability
0.9% · EPSS, next 30 days
Weakness
CWE-787 · Out-of-bounds write
Record status
Analyzed

Affected

Attack profile CVSS 3.1 · 8.8

Attack vector
Local
Complexity
Low
Privileges needed
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Raw vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record