Security news, read and ranked every 30 minutes.
Exploited. On CISA's list since 2026-09-18.
CVE-2026-53266 · Linux Kernel · Published 2026-06-25
8.8 out of 10
CVSS rates it high.
0.9%
Estimated chance of exploitation in the next 30 days, higher than 60% of all scored flaws (EPSS, 2026-10-29).
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 39 days ago (2026-09-21).
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Linux Kernel contains an out-of-bounds write vulnerability in the ebtables SNAT target which allows an ARP sender hardware address rewrite to write directly into a nonlinear socket-buffer fragment backed by a splice-imported file page. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.
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().
From the NVD.
Explore this week’s weaknesses and all learning topics
Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
A program writes outside the memory region it is allowed to use.
CWE-787 · CISA KEV; NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Video course · Free course. C programming and memory concepts are useful; covers several weakness types.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
No story in the last 14 days has mentioned it.
Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.