Patch Forecast
Amber warning
Patch this week.

CVE-2026-64552

Canonical Ubuntu Linux: out-of-bounds write

Risk score
66/100
CVSS
8.4 v3.1
Exploit chance (30 days)
0.1%
Published
27 Jul 2026

Open in the live forecast Today's forecast

What to know

What it is
A vulnerability in the Linux kernel's virtio-net code allows a malicious virtio backend to announce a len in a gap, leading to an out-of-bounds write and potentially allowing an attacker to gain control, impact data integrity, and affect availability. An attacker could exploit this to gain high-level privileges, impact integrity, and affect availability.
Affected
{'product': 'Ubuntu Linux', 'vendor': 'Canonical'}
Fix
Check the linked advisory for the fix
Exploitation
No known exploitation

Story map

Story map: Canonical Ubuntu LinuxTHE FLAWSTHE FIXCVE-2026-64552Out-of-bounds writeCVSS 8.4 · EPSS 0%CVE-2026-93479Heap buffer overflow can leadto remote code executionCVSS 8.1 · EPSS 1%CVE-2026-15176Heap buffer overflow can leadto remote code executionCVSS 8.1 · EPSS 1%CVE-2026-97205NGINX Plus and NGINX OpenSource have a vulnerability inthe ngx_http_core_module…CVSS 8.1 · EPSS 1%FixCheck the linked advisory forthe concrete fix.Who is exposed{'products': ['NGINX Plus','NGINX Open Source'],'packages': [], 'versions': []}RED · ACT TODAYCanonical UbuntuLinuxA vulnerability exists in NGINXPlus and NGINX Open Sourcewhen a map directive uses regexmatching and the root directiveor access log format referencesthe map's regex capturevariables before referencing…Where it standsNo known exploitationHOW IT UNFOLDEDOfficial record on the left, the press on the right, oldest first.26 Oct · Ubuntu security noticesUSN-8955-1: nginx vulnerabilities5 Nov · Ubuntu security noticesUSN-8955-2: nginx vulnerabilities6 Nov · Ubuntu security noticesUSN-9003-1: Linux kernel (NVIDIA) vulnerabilitiesCONNECTS TOSame weaknessOut-of-bounds write (CWE-787)399 other warnings in 30 days →Same productEarlier Canonical Ubuntu Linux warnings147 in the last 90 days →
Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

Canonical Ubuntu Linux: Red, act today. A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. An unauthenticated attacker can exploit this vulnerability by sending crafted HTTP requests, causing a heap buffer overflow in the NGINX worker process leading to a restart, or potential…

The flaws

  • CVE-2026-64552: Out-of-bounds write (CVSS 8.4 · EPSS 0%)
  • CVE-2026-93479: Heap buffer overflow can lead to remote code execution (CVSS 8.1 · EPSS 1%)
  • CVE-2026-15176: Heap buffer overflow can lead to remote code execution (CVSS 8.1 · EPSS 1%)
  • CVE-2026-97205: NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module (CVSS 8.1 · EPSS 1%)

The fix

Fix: Check the linked advisory for the concrete fix.

Who is exposed: {'products': ['NGINX Plus', 'NGINX Open Source'], 'packages': [], 'versions': []}

Where it stands

  • No known exploitation

How it unfolded

  1. 26 Oct, Ubuntu security notices (official): USN-8955-1: nginx vulnerabilities
  2. 5 Nov, Ubuntu security notices (official): USN-8955-2: nginx vulnerabilities
  3. 6 Nov, Ubuntu security notices (official): USN-9003-1: Linux kernel (NVIDIA) vulnerabilities

Connects to

Why it is Amber

  • CVSS 8.4 high
  • On your watchlist: linux kernel
  • Named in a government or vendor bulletin

Government and vendor bulletins

References

Original 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.

Last activity 6 Nov 2026. Patch Forecast updates every hour.