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CVE-2026-93817
perf: Fix addr_filter_ranges lifetime
Published 2026-09-24 (24 days ago) by the Linux kernel CNA. Subsystem kernel/events. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-93817 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Lee Jia Jie reported that since event::addr_filter_ranges is used under RCU, it should be RCU freed.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
kernel/events/core.c
- What this is
- PERFORMANCE EVENTS SUBSYSTEMMAINTAINERS section matched on kernel/events/* · linux-perf-users@vger.kernel.org · Supported
Check it on the machine
grep -w CONFIG_PERF_EVENTS /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12y
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switch
- CONFIG_PERF_EVENTS
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-09-24 (24 days ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- kernel/events
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.7 | 6.12.111 | cd8dab11046c |
| 4.7 | 6.18.53 | 6f1853b2b9f3 |
| 4.7 | 7.2 | e62d4192e593 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The buggy kfree of event->addr_filter_ranges is in __free_event(), reached from close(2) via perf_release() → perf_event_release_kernel() → put_event() → _free_event(). The concurrent use is a local mmap(2)/exec that hits perf_event_mmap()/perf_event_exec() → perf_iterate_ctx(). No remote protocol supplies the triggering state.
- AC:LAttack complexity, low
- The attacker sets attr.inherit, opens an intel_pt/cs_etm event, issues PERF_EVENT_IOC_SET_FILTER, then forks/clones. close() on the parent fd kfree's the child's addr_filter_ranges in __free_event() while the child mmap()s a VM_EXEC mapping so __perf_addr_filters_adjust() writes the freed array. Both sides are attacker-driven.
- PR:LPrivileges required, low
- Default perf_event_paranoid=2 still allows an unprivileged per-task intel_pt or cs_etm event with exclude_kernel set; pt_event_init() and etm_event_init() have no capable() check, and find_get_context() calls perf_allow_cpu() only for pid==-1. PERF_EVENT_IOC_SET_FILTER is then ioctl'd on that fd via perf_ioctl().
- UI:NUser interaction, none
- The attacker performs sys_perf_event_open(), PERF_EVENT_IOC_SET_FILTER, fork/clone, mmap() of the filtered file, and close() entirely in tasks they control. No separate victim must mount a filesystem or open a file.
- S:UScope, unchanged
- The defect is a host-kernel heap UAF of event->addr_filter_ranges in kernel/events/core.c. Impact stays inside the kernel's own security authority and is not a KVM/Xen guest-to-host escape or IOMMU/DMA bypass.
- C:HConfidentiality impact, high
- __free_event() kfree's the kcalloc'd addr_filter_ranges array while RCU walkers still hold the event. Reclaiming that heap object, combined with pt_event_addr_filters_sync()/etm_addr_filters_sync() reading fr[range].start/size, yields a kernel read primitive.
- I:HIntegrity impact, high
- __perf_addr_filters_adjust() and perf_event_addr_filters_exec() write attacker-influenced vma start/size into the already-freed addr_filter_ranges slots. That heap UAF write is sprayable into a control-flow hijack / arbitrary write.
- A:HAvailability impact, high
- Use-after-free of addr_filter_ranges while perf_iterate_ctx() still observes the event on ctx->event_list causes a kernel oops or panic when the freed slots are indexed or the reallocated object is corrupted.