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CVE-2023-53560: tracing/histograms: Add histograms to hist_vars if they have referenced variables

In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Add histograms to hist_vars if they have referenced variables Hist triggers can have referenced variables without having direct variables fields. This can be the case if referenced variables are added for trigger actions. In this case the newly added references will not have field variables. Not taking such referenced variables into consideration can result in a bug where it would be possible to remove hist trigger with variables being refenced. This will result in a bug that is easily reproducable like so $ cd /sys/kernel/tracing $ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events $ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger $ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger $ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger [ 100.263533] ================================================================== [ 100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180 [ 100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439 [ 100.266320] [ 100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4 [ 100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 [ 100.268561] Call Trace: [ 100.268902] <TASK> [ 100.269189] dump_stack_lvl+0x4c/0x70 [ 100.269680] print_report+0xc5/0x600 [ 100.270165] ? resolve_var_refs+0xc7/0x180 [ 100.270697] ? kasan_complete_mode_report_info+0x80/0x1f0 [ 100.271389] ? resolve_var_refs+0xc7/0x180 [ 100.271913] kasan_report+0xbd/0x100 [ 100.272380] ? resolve_var_refs+0xc7/0x180 [ 100.272920] __asan_load8+0x71/0xa0 [ 100.273377] resolve_var_refs+0xc7/0x180 [ 100.273888] event_hist_trigger+0x749/0x860 [ 100.274505] ? kasan_save_stack+0x2a/0x50 [ 100.275024] ? kasan_set_track+0x29/0x40 [ 100.275536] ? __pfx_event_hist_trigger+0x10/0x10 [ 100.276138] ? ksys_write+0xd1/0x170 [ 100.276607] ? do_syscall_64+0x3c/0x90 [ 100.277099] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.277771] ? destroy_hist_data+0x446/0x470 [ 100.278324] ? event_hist_trigger_parse+0xa6c/0x3860 [ 100.278962] ? __pfx_event_hist_trigger_parse+0x10/0x10 [ 100.279627] ? __kasan_check_write+0x18/0x20 [ 100.280177] ? mutex_unlock+0x85/0xd0 [ 100.280660] ? __pfx_mutex_unlock+0x10/0x10 [ 100.281200] ? kfree+0x7b/0x120 [ 100.281619] ? ____kasan_slab_free+0x15d/0x1d0 [ 100.282197] ? event_trigger_write+0xac/0x100 [ 100.282764] ? __kasan_slab_free+0x16/0x20 [ 100.283293] ? __kmem_cache_free+0x153/0x2f0 [ 100.283844] ? sched_mm_cid_remote_clear+0xb1/0x250 [ 100.284550] ? __pfx_sched_mm_cid_remote_clear+0x10/0x10 [ 100.285221] ? event_trigger_write+0xbc/0x100 [ 100.285781] ? __kasan_check_read+0x15/0x20 [ 100.286321] ? __bitmap_weight+0x66/0xa0 [ 100.286833] ? _find_next_bit+0x46/0xe0 [ 100.287334] ? task_mm_cid_work+0x37f/0x450 [ 100.287872] event_triggers_call+0x84/0x150 [ 100.288408] trace_event_buffer_commit+0x339/0x430 [ 100.289073] ? ring_buffer_event_data+0x3f/0x60 [ 100.292189] trace_event_raw_event_sys_enter+0x8b/0xe0 [ 100.295434] syscall_trace_enter.constprop.0+0x18f/0x1b0 [ 100.298653] syscall_enter_from_user_mode+0x32/0x40 [ 100.301808] do_syscall_64+0x1a/0x90 [ 100.304748] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.307775] RIP: 0033:0x7f686c75c1cb [ 100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48 [ 100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 [ 100.321200] RA ---truncated---

UnknownCVSS not scoredNot KEV-listedUpdated
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2023-53560 is a Linux kernel tracing bug. A specially arranged tracing histogram setup can leave references to freed memory, producing a kernel use-after-free report. The bundle does not provide CVSS, CWE, confirmed real-world exploitation, or distribution package names, so urgency depends on whether affected kernels expose tracing controls to trusted operators only.

Executive priority

Treat this as a kernel maintenance and access-control issue. Prioritize patching on shared, multi-user, container-host, and developer systems where non-root users might gain tracing access. No source in the bundle supports emergency handling for active exploitation.

Technical view

The issue is in Linux tracing histograms. Hist triggers with variables referenced by trigger actions were not always added to hist_vars, allowing removal of a histogram while another trigger still referenced its variables. The provided crash shows KASAN slab-use-after-free in resolve_var_refs after tracefs trigger manipulation.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions listed in the CVE bundle, including 4.17, 4.19.291, 5.4.251, 5.10.188, 5.15.121, 6.1.40, 6.4.5, and 6.5. Practical exposure depends on who can write tracing trigger configuration under tracefs.

Exploitation context

The source includes a reproducible local trigger sequence but KEV is false and no cited source confirms active exploitation. The bundle supports a local kernel memory safety bug in tracing configuration, not remote exploitation or public weaponization.

Researcher notes

Evidence is strongest for a local tracefs-triggered use-after-free in kernel tracing histograms. The bundle lacks CVSS, CWE, exploit status, and distro mappings. Avoid assuming privilege escalation; validate prerequisites around tracing permissions, affected kernel lineage, and whether stable fixes are backported.

Mitigation direction

  • Identify Linux kernel versions across exposed systems.
  • Apply vendor kernel updates that include the referenced stable fixes.
  • If updates are pending, restrict tracefs and tracing trigger write access.
  • Check distribution advisories for exact package names and backport status.

Validation and detection

  • Compare running kernel versions against vendor-fixed package guidance.
  • Confirm tracefs trigger write access is limited to authorized administrators.
  • Review kernel changelogs for the referenced stable commit IDs.
  • Monitor logs for KASAN or kernel reports involving resolve_var_refs.
Prepared
Confidence
medium
Sources
9

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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CVE-2023-53560 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
8Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13, 067fe038e70f6e64960d26a79c4df5f1413d0f13unaffected
LinuxLinux4.17, 0, 4.19.291, 5.4.251, 5.10.188, 5.15.121, 6.1.40, 6.4.5, 6.5affected
Weakness

CWE details

No CWE listed

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