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NVD / CVE Program· CNA Linux

CVE-2025-39683: tracing: Limit access to parser->buffer when trace_get_user failed

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3079517a5ba80901fe828a06998da64b9b8749be, 4.10, 4.15; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.

Low priority for now. Upgrade to Linux Linux 3079517a5ba80901fe828a06998da64b9b8749be, 4.10, 4.15; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: tracing: Limit access to parser->buffer when trace_get_user failed When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered: BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165 CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0 __asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618 __fput+0x364/0xa58 ____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0 The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0. Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Sep 5, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.1
CNA · Linux
7.8
0.7 point gap

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel4.9.269 and later · before 4.10
  • linux linux kernel4.14.233 and later · before 4.15
  • linux linux kernel4.19.191 and later · before 4.20
  • linux linux kernel5.4.118 and later · before 5.5
  • linux linux kernel5.10.36 and later · before 5.10.241
  • linux linux kernel5.11.20 and later · before 5.12
  • linux linux kernel4.4.269 and later · before 4.5
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel6.7 and later · before 6.12.44
  • linux linux kernel6.13 and later · before 6.16.4
  • linux linux kernel5.12.3 and later · before 5.15.190
  • linux linux kernel6.17

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 24cd31752f47699b89b4b3471155c8e599a1a23a, e9cb474de7ff7a970c2a3951c12ec7e3113c0c35, 6ab671191f64b0da7d547e2ad4dc199ca7e5b558, 3d9281a4ac7171c808f9507f0937eb236b353905, 0b641b25870f02e2423e494365fc5243cc1e2759, ffd51dbfd2900e50c71b5c069fe407957e52d61f, cdd107d7f18158d966c2bc136204fe826dac445c, 5.13affected
    • 634684d79733124f7470b226b0f42aada4426b07 and later · before b842ef39c2ad6156c13afdec25ecc6792a9b67b9affected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before 41b838420457802f21918df66764b6fbf829d330affected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before 418b448e1d7470da9d4d4797f71782595ee69c49affected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before 58ff8064cb4c7eddac4da1a59da039ead586950aaffected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before d0c68045b8b0f3737ed7bd6b8c83b7887014adeeaffected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before 3079517a5ba80901fe828a06998da64b9b8749beaffected · git
    • 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 and later · before 6a909ea83f226803ea0e718f6e88613df9234d58affected · git
    • 5.10.36 and later · before 5.10.241affected · semver
    • 4.4.269 and later · before 4.5affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.48-16.12.48-1
Debian:14linuxbefore 6.16.5-16.16.5-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39681Sep 5, 2025 · x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper
    22Monitor
  • ← EarlierCVE-2025-39682Sep 5, 2025 · tls: fix handling of zero-length records on the rx_listKEV
    70This week
  • Later →CVE-2025-39684Sep 5, 2025 · comedi: Fix use of uninitialized memory in do_insn_ioctl() and do_insnlist_ioctl()
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3079517a5ba80901fe828a06998da64b9b8749beVendor (CNA)
Linux Linux4.10Vendor (CNA)
Linux Linux4.15Vendor (CNA)
Linux Linux4.20Vendor (CNA)
Linux Linux4.5Vendor (CNA)
Linux Linux418b448e1d7470da9d4d4797f71782595ee69c49Vendor (CNA)
Linux Linux41b838420457802f21918df66764b6fbf829d330Vendor (CNA)
Linux Linux5.10.241Vendor (CNA)
Linux Linux5.12Vendor (CNA)
Linux Linux5.13Vendor (CNA)
Linux Linux5.5Vendor (CNA)
Linux Linux58ff8064cb4c7eddac4da1a59da039ead586950aVendor (CNA)
Linux Linux6a909ea83f226803ea0e718f6e88613df9234d58Vendor (CNA)
Linux Linuxb842ef39c2ad6156c13afdec25ecc6792a9b67b9Vendor (CNA)
Linux Linuxd0c68045b8b0f3737ed7bd6b8c83b7887014adeeVendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (10 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records