CVE-2026-64552: Linux kernel · virtio-net: fix len check in receive_big()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.4 High · fixed in fbeb65154583879d556ea94cb2f15888e9470f3d : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in fbeb65154583879d556ea94cb2f15888e9470f3d, f9451d0fd5ba635dcabb49bfe456a6db734a8986, e6b8463b7d791f3886d7584259d6e9f06a69f12e +7
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: virtio-net: fix len check in receive_big() receive_big() bounds the device-announced length by (big_packets_num_skbfrags + 1) * PAGE_SIZE. That is still too loose: add_recvbuf_big() sets sg[1] to start at offset sizeof(struct padded_vnet_hdr) into the first page, so the chain actually carries hdr_len + (PAGE_SIZE - sizeof(padded_vnet_hdr)) + big_packets_num_skbfrags * PAGE_SIZE bytes -- 20 bytes less than the check allows for the common hdr_len == 12 case. A malicious virtio backend can announce a len in that gap. page_to_skb() then walks one frag past the page chain, storing a NULL page->private into skb_shinfo()->frags[MAX_SKB_FRAGS], which is both an out-of-bounds write past the static frag array and a NULL frag handed up the rx path. Bound len by the size add_recvbuf_big() actually advertised.
References
- git.kernel.org/stable/c/f9451d0fd5ba635dcabb49bfe456a6db734a8986 (opens in a new tab)
- git.kernel.org/stable/c/38e94d63e29f4a5c6eae87ee2c02101aaa321502 (opens in a new tab)
- git.kernel.org/stable/c/fbeb65154583879d556ea94cb2f15888e9470f3d (opens in a new tab)
- git.kernel.org/stable/c/c7fc9adf4e006155f7f2aeda052fbcde25cdcc49 (opens in a new tab)
- git.kernel.org/stable/c/e6b8463b7d791f3886d7584259d6e9f06a69f12e (opens in a new tab)
- git.kernel.org/stable/c/9e5ad06ea826322ce8c58b4a68442a96f600c3c4 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)