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NVD / CVE Program· CNA Linux

CVE-2026-31607: usbip: validate number_of_packets in usbip_pack_ret_submit()

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.31% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 2.6.33, 2.6.34, 2.6.35; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 2.6.33, 2.6.34, 2.6.35; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes 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: usbip: validate number_of_packets in usbip_pack_ret_submit() When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets from the network PDU. This value is subsequently used as the loop bound in usbip_recv_iso() and usbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible array whose size was fixed at URB allocation time based on the *original* number_of_packets from the CMD_SUBMIT. A malicious USB/IP server can set number_of_packets in the response to a value larger than what was originally submitted, causing a heap out-of-bounds write when usbip_recv_iso() writes to urb->iso_frame_desc[i] beyond the allocated region. KASAN confirmed this with kernel 7.0.0-rc5: BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640 Write of size 4 at addr ffff888106351d40 by task vhci_rx/69 The buggy address is located 0 bytes to the right of allocated 320-byte region [ffff888106351c00, ffff888106351d40) The server side (stub_rx.c) and gadget side (vudc_rx.c) already validate number_of_packets in the CMD_SUBMIT path since commits c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") and b78d830f0049 ("usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input"). The server side validates against USBIP_MAX_ISO_PACKETS because no URB exists yet at that point. On the client side we have the original URB, so we can use the tighter bound: the response must not exceed the original number_of_packets. This mirrors the existing validation of actual_length against transfer_buffer_length in usbip_recv_xbuff(), which checks the response value against the original allocation size. Kelvin Mbogo's series ("usb: usbip: fix integer overflow in usbip_recv_iso()", v2) hardens the receive-side functions themselves; this patch complements that work by catching the bad value at its source -- in usbip_pack_ret_submit() before the overwrite -- and using the tighter per-URB allocation bound rather than the global USBIP_MAX_ISO_PACKETS limit. Fix this by checking rpdu->number_of_packets against urb->number_of_packets in usbip_pack_ret_submit() before the overwrite. On violation, clamp to zero so that usbip_recv_iso() and usbip_pad_iso() safely return early.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Apr 24, 2026
Updated
Oct 19, 2026
EPSS
0.3% · 24th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
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.

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Noroxi analysis

What does it mean in your environment?

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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

Affected versions

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

  • linux linux kernel2.6.39 and later · before 6.6.136
  • linux linux kernel6.7 and later · before 6.12.83
  • linux linux kernel6.13 and later · before 6.18.24
  • linux linux kernel6.19 and later · before 6.19.14
  • linux linux kernel7.0 and later · before 7.0.1

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

    • d9638d9236eed035a575feddec61d036dacc2676, ca7d3501b7a287c18b5b470e871d3029b0f4842a, 1ce528277e1a66856ed3f7526c1e3458c0ed4a70, db898d0c5c493ce4177d5e1d3a953e079a56a24b, 5aa02704b9ee67c5b2ee26d54c5f4eb99e93ba9a, 2.6.39affected
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 324262c38438255bf6bdbf6342ca47c0badaab76affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 973f2c250289f5bf6cc146b98aa6fdde11fe50d6affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before ce744264b06b97069b3722511ab355738311fee0affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 885c8591784da6314f9aa82fa460ac69f9f79e5faffected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 8d155e2d1c4102f74f82a2bf9c016164bb0f7384affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 906f16a836de13fe61f49cdce2f66f2dbd14caf4affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before ef8ebb1c637b4cfb61a9dd2e013376774ee2033baffected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 5e1c4ece08ccdc197177631f111845a2c68eede3affected · git
    • 1325f85fa49f57df034869de430f7c302ae23109 and later · before 2ab833a16a825373aad2ba7d54b572b277e95b71affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.16.1.el10_26.12.0-211.16.1.el10_2

+96

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-2026-31604Apr 24, 2026 · wifi: rtw88: fix device leak on probe failure
    22Monitor
  • ← EarlierCVE-2026-31606Apr 24, 2026 · usb: gadget: f_hid: don't call cdev_init while cdev in use
    22Monitor
  • Later →CVE-2026-31609Apr 24, 2026 · smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()
    39Monitor

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 Linux2.6.33Vendor (CNA)
Linux Linux2.6.34Vendor (CNA)
Linux Linux2.6.35Vendor (CNA)
Linux Linux2.6.36Vendor (CNA)
Linux Linux2.6.39Vendor (CNA)
Linux Linux2ab833a16a825373aad2ba7d54b572b277e95b71Vendor (CNA)
Linux Linux324262c38438255bf6bdbf6342ca47c0badaab76Vendor (CNA)
Linux Linux5e1c4ece08ccdc197177631f111845a2c68eede3Vendor (CNA)
Linux Linux885c8591784da6314f9aa82fa460ac69f9f79e5fVendor (CNA)
Linux Linux8d155e2d1c4102f74f82a2bf9c016164bb0f7384Vendor (CNA)
Linux Linux906f16a836de13fe61f49cdce2f66f2dbd14caf4Vendor (CNA)
Linux Linux973f2c250289f5bf6cc146b98aa6fdde11fe50d6Vendor (CNA)
Linux Linuxce744264b06b97069b3722511ab355738311fee0Vendor (CNA)
Linux Linuxef8ebb1c637b4cfb61a9dd2e013376774ee2033bVendor (CNA)
azl3 kernel 6.6.134.1-2 on Azure Linux 3.06.6.137.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.10.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-687.10.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+19

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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • 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
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 (17 more)

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

All records