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CVE-2026-64570

Canonical Ubuntu Linux: double free

Risk score
63/100
CVSS
7.8 v3.1
Exploit chance (30 days)
0.2%
Published
5 Aug 2026

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What to know

What it is
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix fils_discovery double free on alloc failure ieee80211_set_fils_discovery() calls kfree_rcu() on the old template before allocating the replacement. If the kzalloc() then fails, it returns -ENOMEM while link->u.ap.fils_discovery sti…
Affected
Canonical Ubuntu Linux
Fix
Apply the vendor's security update; see the linked advisory.
Exploitation
No known exploitation

Story map

Story map: Canonical Ubuntu LinuxTHE FLAWSTHE FIXCVE-2026-64570Double freeCVSS 7.8 · 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 weaknessDouble free (CWE-415)55 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-2026-64570: Double free (CVSS 7.8 · 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 7.8 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: wifi: mac80211: fix fils_discovery double free on alloc failure ieee80211_set_fils_discovery() calls kfree_rcu() on the old template before allocating the replacement. If the kzalloc() then fails, it returns -ENOMEM while link->u.ap.fils_discovery still points at the object already queued for freeing. A later update or AP teardown (ieee80211_stop_ap()) re-queues that same rcu_head; the second free is caught by KASAN when the RCU sheaf is processed in softirq: BUG: KASAN: double-free in rcu_free_sheaf (mm/slub.c:5850) Free of addr ffff88800c065280 by task swapper/0/0 ... __rcu_free_sheaf_prepare (mm/slub.c:2634 mm/slub.c:2940) rcu_free_sheaf (mm/slub.c:5850) rcu_core (kernel/rcu/tree.c:2617 kernel/rcu/tree.c:2869) handle_softirqs (kernel/softirq.c:622) The buggy address belongs to the cache kmalloc-96 of size 96 Queue the old object for kfree_rcu() only after the new one is published, matching ieee80211_set_probe_resp() and ieee80211_set_s1g_short_beacon().

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