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NVD / CVE Program· CNA Linux

CVE-2025-38480: comedi: Fix use of uninitialized data in insn_rw_emulate_bits()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.19% (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 10f9024a8c824a41827fff1fefefb314c98e2c88, 16256d7efcf7acc9f39abe21522c4c6b77f67c00, 2af1e7d389c2619219171d23f5b96dbcbb7f9656; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1.

Low priority for now. Upgrade to Linux Linux 10f9024a8c824a41827fff1fefefb314c98e2c88, 16256d7efcf7acc9f39abe21522c4c6b77f67c00, 2af1e7d389c2619219171d23f5b96dbcbb7f9656; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1 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: comedi: Fix use of uninitialized data in insn_rw_emulate_bits() For Comedi `INSN_READ` and `INSN_WRITE` instructions on "digital" subdevices (subdevice types `COMEDI_SUBD_DI`, `COMEDI_SUBD_DO`, and `COMEDI_SUBD_DIO`), it is common for the subdevice driver not to have `insn_read` and `insn_write` handler functions, but to have an `insn_bits` handler function for handling Comedi `INSN_BITS` instructions. In that case, the subdevice's `insn_read` and/or `insn_write` function handler pointers are set to point to the `insn_rw_emulate_bits()` function by `__comedi_device_postconfig()`. For `INSN_WRITE`, `insn_rw_emulate_bits()` currently assumes that the supplied `data[0]` value is a valid copy from user memory. It will at least exist because `do_insnlist_ioctl()` and `do_insn_ioctl()` in "comedi_fops.c" ensure at lease `MIN_SAMPLES` (16) elements are allocated. However, if `insn->n` is 0 (which is allowable for `INSN_READ` and `INSN_WRITE` instructions, then `data[0]` may contain uninitialized data, and certainly contains invalid data, possibly from a different instruction in the array of instructions handled by `do_insnlist_ioctl()`. This will result in an incorrect value being written to the digital output channel (or to the digital input/output channel if configured as an output), and may be reflected in the internal saved state of the channel. Fix it by returning 0 early if `insn->n` is 0, before reaching the code that accesses `data[0]`. Previously, the function always returned 1 on success, but it is supposed to be the number of data samples actually read or written up to `insn->n`, which is 0 in this case.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jul 28, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • A fix has been released

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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 kernel5.5 and later · before 5.10.241
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.147
  • linux linux kernel2.6.29 and later · before 5.4.297
  • linux linux kernel6.7 and later · before 6.12.40
  • linux linux kernel6.13 and later · before 6.15.8
  • linux linux kernel6.2 and later · before 6.6.100
  • linux linux kernel6.16

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

    • 2.6.29affected
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 4c2981bf30401adfcdbfece4ab6f411f7c5875a1affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 16256d7efcf7acc9f39abe21522c4c6b77f67c00affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before c53570e62b5b28bdb56bb563190227f8307817a5affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 3050d197d6bc9ef128944a70210f42d2430b3000affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 10f9024a8c824a41827fff1fefefb314c98e2c88affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 2af1e7d389c2619219171d23f5b96dbcbb7f9656affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before 3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870affected · git
    • ed9eccbe8970f6eedc1b978c157caf1251a896d4 and later · before e9cb26291d009243a4478a7ffb37b3a9175bfce9affected · git
    • before 2.6.29not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.147-16.1.147-1
Debian:13linuxbefore 6.12.41-16.12.41-1
Debian:14linuxbefore 6.16.3-16.16.3-1

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-2025-38476Jul 28, 2025 · rpl: Fix use-after-free in rpl_do_srh_inline().
    31Monitor
  • ← EarlierCVE-2025-38477Jul 28, 2025 · net/sched: sch_qfq: Fix race condition on qfq_aggregate
    18Monitor
  • Later →CVE-2025-38481Jul 28, 2025 · comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large
    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 Linux10f9024a8c824a41827fff1fefefb314c98e2c88Vendor (CNA)
Linux Linux16256d7efcf7acc9f39abe21522c4c6b77f67c00Vendor (CNA)
Linux Linux2af1e7d389c2619219171d23f5b96dbcbb7f9656Vendor (CNA)
Linux Linux3050d197d6bc9ef128944a70210f42d2430b3000Vendor (CNA)
Linux Linux3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870Vendor (CNA)
Linux Linux4c2981bf30401adfcdbfece4ab6f411f7c5875a1Vendor (CNA)
Linux Linuxc53570e62b5b28bdb56bb563190227f8307817a5Vendor (CNA)
Linux Linuxe9cb26291d009243a4478a7ffb37b3a9175bfce9Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.147-1 · 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.

  • CVE-2024-50302251 days apartHID: core: zero-initialize the report bufferKEV
    52Plan
  • CVE-2026-52989331 days apartnvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers
    39Monitor
  • CVE-2024-47685280 days apartnetfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()
    36Monitor
  • CVE-2026-53225332 days apartsctp: fix uninit-value in __sctp_rcv_asconf_lookup()
    36Monitor
  • CVE-2026-53170332 days apartaccel/ethosu: reject DMA commands with uninitialized length
    35Monitor
  • CVE-2026-43139282 days apartxfrm6: fix uninitialized saddr in xfrm6_get_saddr()
    34Monitor

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
none
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
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-908 · Use of Uninitialized Resource

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

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

Change log

  1. Fix✗ → ✓

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

References

Show all references (9 more)

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

All records