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CVE-2026-64299
tracing: Prevent out-of-bounds read in glob matching
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem include/linux. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-64299 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 | fixedDLA-4720-1 · 2026-08-05 · text | 6.1.180-1 | Update the kernel and reboot. DLA-4720-1 shipped the fix on 2026-08-05, in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.96-1 | Update the kernel and reboot. Fixed in 6.12.96-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4724-1 · 2026-08-07 · text | 6.12.100-1~deb12u1 | Update the kernel and reboot. DLA-4724-1 shipped the fix on 2026-08-07, in 6.12.100-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
String event fields are not necessarily NUL-terminated, so the filter predicate functions (filter_pred_string(), filter_pred_strloc() and filter_pred_strrelloc()) pass the field length to the regex match callbacks, and the length-aware matchers honour it. regex_match_glob() was the exception: it ignored the length and called glob_match(), which scans the string until it hits a NUL byte. Some string fields are not NUL-terminated. One example is the dynamic char array of the xfs_* namespace tracepoints, which is copied without a trailing NUL. For such a field, glob matching reads past the end of the event field, causing a KASAN slab-out-of-bounds read in glob_match(), reached via regex_match_glob() and filter_match_preds() from the xfs_lookup tracepoint. Add a length-bounded glob_match_len() and use it from regex_match_glob() so glob matching always stops at the field boundary. The matching loop is factored into a shared helper so glob_match() keeps its behaviour.
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.
include/linux/glob.h
kernel/trace/trace_events_filter.c
lib/glob.c
- What this is
- TRACINGMAINTAINERS section matched on kernel/trace/ · linux-kernel@vger.kernel.org · Maintained
Check it on the machine
grep -wE 'CONFIG_EVENT_TRACING|CONFIG_FUNCTION_TRACER|CONFIG_RETHOOK|CONFIG_RING_BUFFER|CONFIG_TRACEPOINTS|CONFIG_TRACE_CLOCK|CONFIG_TRACING' /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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormYnot built on arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieYnot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- forky, sidYnot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae
- bookworm · linux-6.12Ynot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- Y
- built in where it is built at all; some flavours do not build it
- Build switches
- CONFIG_EVENT_TRACING, CONFIG_FUNCTION_TRACER, CONFIG_RETHOOK, CONFIG_RING_BUFFER, CONFIG_TRACEPOINTS, CONFIG_TRACE_CLOCK, CONFIG_TRACING
- Reads as
- all on means the file is compiled; any one off means it is not.
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
- 2026-07-25 (3 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 5.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- include/linux
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.10 | 5.10.261 | 265f3a690f6c |
| 4.10 | 5.15.212 | ee5b8888d324 |
| 4.10 | 6.1.178 | 56d4c9ab8471 |
| 4.10 | 6.6.145 | 35ae19764eab |
| 4.10 | 6.12.96 | ebb559028569 |
| 4.10 | 6.18.39 | 2dad64a97e1d |
| 4.10 | 7.1.4 | e5d5f3bd053a |
| 4.10 | 7.2 | 0a6070839b1e |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4724-1 | 2026-08-07 | bookworm 6.12.100-1~deb12u1 | tracker |
| DLA-4723-1 | 2026-08-07 | bullseye 6.1.180-1~deb11u1 | tracker |
| DLA-4720-1 | 2026-08-05 | bookworm 6.1.180-1 | tracker |
| DLA-4717-1 | 2026-08-05 | bullseye 5.10.262-1 | 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 attacker installs a glob filter through tracefs or perf_event_open and triggers it using a local pathname syscall on an affected filesystem such as XFS. Network clients cannot normally install or observe the required tracing filter.
- AC:LAttack complexity, low
- No race or uncontrollable timing is required; the attacker selects a full-glob pattern and triggers a non-NUL-terminated event field repeatedly. Reused per-CPU trace buffers can also be groomed by attacker-controlled events.
- PR:LPrivileges required, low
- Although user namespaces alone cannot bypass tracefs or initial-namespace perf capability checks, ordinary users can install filters when tracefs access is delegated to a tracing group or perf_event_paranoid permits kernel events. These are supported and reasonable deployments requiring only basic user privileges.
- UI:NUser interaction, none
- The attacker can install the filter and trigger pathname lookups directly without another user's action.
- S:UScope, unchanged
- The out-of-bounds read affects the host kernel within the same security authority and does not cross a guest-host, hypervisor, or IOMMU boundary.
- C:HConfidentiality impact, high
- glob_match() ignores the supplied field length and scans until an incidental NUL, allowing filter results to act as an oracle over adjacent or reused kernel trace-buffer data. The read is not strictly bounded to a few bytes.
- I:NIntegrity impact, none
- The vulnerable code only reads memory and changes the Boolean filter result; it provides no out-of-bounds write or other memory-modification primitive.
- A:HAvailability impact, high
- The repeatable unbounded scan can cross the event allocation or page boundary, producing the reported KASAN invalid access and potentially an oops or panic on inaccessible or poisoned memory. Panic-on-warning configurations make total availability loss directly achievable.