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NVD / CVE Program· CNA Linux

CVE-2025-40044: fs: udf: fix OOB read in lengthAllocDescs handling

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 14496175b264d30c2045584ee31d062af2e3a660, 1d1847812a1a5375c10a2a779338df643f79c047, 3bd5e45c2ce30e239d596becd5db720f7eb83c99; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-2.

Low priority for now. Upgrade to Linux Linux 14496175b264d30c2045584ee31d062af2e3a660, 1d1847812a1a5375c10a2a779338df643f79c047, 3bd5e45c2ce30e239d596becd5db720f7eb83c99; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-2 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: fs: udf: fix OOB read in lengthAllocDescs handling When parsing Allocation Extent Descriptor, lengthAllocDescs comes from on-disk data and must be validated against the block size. Crafted or corrupted images may set lengthAllocDescs so that the total descriptor length (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer, leading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and trigger a KASAN use-after-free read. BUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 Read of size 1 at addr ffff888041e7d000 by task syz-executor317/5309 CPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261 udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179 extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46 udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106 udf_release_file+0xc1/0x120 fs/udf/file.c:185 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:939 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Validate the computed total length against epos->bh->b_size. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 28, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 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
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

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

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  • when exploit code appears or is weaponized
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  • 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.

—

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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 14496175b264d30c2045584ee31d062af2e3a660affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before d2ed9aa8ae50fb0d4ac5ab07e4c67ba7e9a24818affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 1d1847812a1a5375c10a2a779338df643f79c047affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 918649364fbca7d5df72522ca795479edcd25f91affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before a70dcfa8d0a0cc530a6af59483dfca260b652c1baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 459404f858213967ccfff336c41747d8dd186d38affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3bd5e45c2ce30e239d596becd5db720f7eb83c99affected · git
    • before 2.6.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.158-16.1.158-1
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40042Oct 28, 2025 · tracing: Fix race condition in kprobe initialization causing NULL pointer dereference
    0Monitor
  • ← EarlierCVE-2025-40043Oct 28, 2025 · net: nfc: nci: Add parameter validation for packet data
    35Monitor
  • Later →CVE-2025-40045Oct 28, 2025 · ASoC: codecs: wcd937x: set the comp soundwire port correctly
    31Monitor

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 Linux14496175b264d30c2045584ee31d062af2e3a660Vendor (CNA)
Linux Linux1d1847812a1a5375c10a2a779338df643f79c047Vendor (CNA)
Linux Linux3bd5e45c2ce30e239d596becd5db720f7eb83c99Vendor (CNA)
Linux Linux459404f858213967ccfff336c41747d8dd186d38Vendor (CNA)
Linux Linux918649364fbca7d5df72522ca795479edcd25f91Vendor (CNA)
Linux Linuxa70dcfa8d0a0cc530a6af59483dfca260b652c1bVendor (CNA)
Linux Linuxb57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24Vendor (CNA)
Linux Linuxd2ed9aa8ae50fb0d4ac5ab07e4c67ba7e9a24818Vendor (CNA)
azl3 kernel 6.6.104.2-4 on Azure Linux 3.06.6.112.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.158-1 · 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.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

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

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

References

Show all references (7 more)

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

All records