CVE-2026-52940
CVE.org · Published
- Record status
- Published
- Identifier year (not publication year)
- 2026
- Source publication
- Source updated
- Imported by cveboard
- Source snapshot
- cve_2026-10-24_midnight_baseline ·
CNA source text (English)
tun: zero the whole vnet header in tun_put_user()
In the Linux kernel, the following vulnerability has been resolved: tun: zero the whole vnet header in tun_put_user() tun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel without zeroing it. For a non-tunnel skb, virtio_net_hdr_tnl_from_skb() only initializes the first 10 bytes (sizeof(struct virtio_net_hdr)), leaving bytes 10..23 (num_buffers and the hash/tunnel fields) as stack garbage. An unprivileged user can set the vnet header size to 24 with TUNSETVNETHDRSZ, so __tun_vnet_hdr_put() copies all 24 bytes of the partially-initialized struct to userspace, leaking 14 bytes of kernel stack on every read of a non-tunnel packet. Fix it the same way tun_get_user() already does by zeroing the whole header right after declaration.
Scoped product and version facts
Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.
Exploitation unknown; this catalogue does not assess exploitation.
Linux
- Vendor
- Linux
- Product
- Linux
- Platforms
- Unknown
- Default status
unaffected
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 288f30435132d2f9e7a29ec9b9745a4f9dc7fd37 | affected | git | 5fd1fa5a4254bfdd70571c77f5e3bcb4e43738d5 | Unavailable | None listed |
| 288f30435132d2f9e7a29ec9b9745a4f9dc7fd37 | affected | git | 585cb85e9a29185be05f326369573c2663cf4380 | Unavailable | None listed |
| 288f30435132d2f9e7a29ec9b9745a4f9dc7fd37 | affected | git | 7f2fcff15e99bb852f6967396ed12b38376e2c8d | Unavailable | None listed |
Linux
- Vendor
- Linux
- Product
- Linux
- Platforms
- Unknown
- Default status
affected
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 6.17 | affected | Unavailable | Unavailable | Unavailable | None listed |
| 0 | unaffected | semver | 6.17 | Unavailable | None listed |
| 6.18.36 | unaffected | semver | Unavailable | 6.18.* | None listed |
| 7.0.13 | unaffected | semver | Unavailable | 7.0.* | None listed |
| 7.1 | unaffected | original_commit_for_fix | Unavailable | * | None listed |