netfilter: bridge: make ebt_snat ARP rewrite writable (Linux Linux)

CVE-2026-53266
HIGH 8.8CISA KEV ↗Exploited per ENISA since 2026-09-18

At a glance

Source
NVD
EPSS
EPSS 0.93 % · percentile 61 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Analyzed

Description

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().

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HLinux
CVSS 3.1HIGH 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 63137bc5882a1882c553d389fdeeeace86ee1741 < bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 ; affected 63137bc5882a1882c553d389fdeeeace86ee1741 < 76280b78cc9f23bdc6438e10ad6dff148ef8375b ; affected 63137bc5882a1882c553d389fdeeeace86ee1741 < b7e91939ba9be805a62a257fa4e227dffbb88fa0 ; affected 63137bc5882a1882c553d389fdeeeace86ee1741 < afd64b59c3de9bbbdd3759e834fdc55cda716e0b ; affected 63137bc5882a1882c553d389fdeeeace86ee1741 < 153ea96c806aea395daba907a4f88480b6ad5093 ; affected 63137bc5882a1882c553d389fdeeeace86ee1741 < b18675263db1147c8e1cab625400c13a0d87bd2d
Linux · Linuxaffected 5.10 ; unaffected 0 < 5.10 ; unaffected 5.10.259 ≤ 5.10.* ; unaffected 5.15.210 ≤ 5.15.* ; unaffected 6.1.176 ≤ 6.1.* ; unaffected 6.6.143 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
CISA Known Exploited VulnerabilitiesCC0 1.0
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD