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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98773: USB: cdc-acm: skip URB restart in port_shutdown if disconnected

—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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).
  • Fixed version: Linux Linux 420ca35af891d33522cc08504768ccd60a4c450a, 6.1.191, 6.12.113; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.

Low priority for now. Upgrade to Linux Linux 420ca35af891d33522cc08504768ccd60a4c450a, 6.1.191, 6.12.113; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 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: USB: cdc-acm: skip URB restart in port_shutdown if disconnected acm_port_shutdown() is called from the tty-port machinery whenever the last user closes the port. acm_disconnect() sets acm->disconnected and calls tty_port_tty_vhangup(), which eventually triggers port_shutdown(). At that point acm_disconnect() has already called acm_poison_urbs() and is about to free the control and read URBs. However, acm_port_shutdown() unconditionally calls acm_unpoison_urbs() and, when the ALWAYS_POLL_CTRL quirk is set, immediately re-submits the ctrlurb and all read URBs. If the concurrent acm_disconnect() then frees those URBs and their DMA buffers while they are in-flight, the result is a use-after-free in acm_ctrl_irq() or acm_read_bulk_callback() accessing the freed DMA memory. Fix by checking acm->disconnected after draining the delayed anchor and returning early: if we are in a disconnect path the URBs must remain poisoned and must not be resubmitted. The early return is placed after the delayed-anchor drain loop because that loop only cancels write-side accounting (wb->use = false and autopm counter) and does not touch the hardware path.

Published
Oct 18, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • Not in KEV: no record of exploitation in the wild
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  • A fix has been released

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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.

—

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

    • 283f8162cc3c82086537cbc7dc01870dbeb07a91, f77f10bc76c2da86b4248269472f6d971e37828b, 7.1affected
    • d826061aa64cb28089bf4c73e301dd7928662b84 and later · before d97da42e9de577dc827d4e8866e6971deefe2d9caffected · git
    • 8fb82e3555a7d56a05d8ef0edee9859f889c0860 and later · before d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0affected · git
    • 603d5a7110832e10165d21f9a1486399457177de and later · before 9742905d9ed5bf23ebe4c100dec80b6bc50fb522affected · git
    • 5d29d7ff8679e5a525f22da467ba33c042e8029b and later · before a0ed07b5bbb2d8fcef86810453216070691816e7affected · git
    • f58752ebcb35e156c85cd1a82d6579c7af3b9023 and later · before 420ca35af891d33522cc08504768ccd60a4c450aaffected · git
    • f58752ebcb35e156c85cd1a82d6579c7af3b9023 and later · before dc614d6bc991740d41d5a99ac7765c4b675dda88affected · git
    • 6.1.175 and later · before 6.1.191affected · semver
    • 6.6.136 and later · before 6.6.160affected · semver
    • 6.12.83 and later · before 6.12.113affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.10-17.2.10-1

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-2026-98771Oct 18, 2026 · usb: storage: sierra_ms: reject short SWoC info transfers
    0Monitor
  • ← EarlierCVE-2026-98772Oct 18, 2026 · USB: serial: fix port tear down use-after-free
    0Monitor
  • Later →CVE-2026-98774Oct 18, 2026 · rust_binder: cancel deferred work items in thread exit
    0Monitor

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 Linux420ca35af891d33522cc08504768ccd60a4c450aVendor (CNA)
Linux Linux6.1.191Vendor (CNA)
Linux Linux6.12.113Vendor (CNA)
Linux Linux6.18.56Vendor (CNA)
Linux Linux6.20Vendor (CNA)
Linux Linux6.6.160Vendor (CNA)
Linux Linux7.1Vendor (CNA)
Linux Linux9742905d9ed5bf23ebe4c100dec80b6bc50fb522Vendor (CNA)
Linux Linuxa0ed07b5bbb2d8fcef86810453216070691816e7Vendor (CNA)
Linux Linuxd86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0Vendor (CNA)
Linux Linuxd97da42e9de577dc827d4e8866e6971deefe2d9cVendor (CNA)
Linux Linuxdc614d6bc991740d41d5a99ac7765c4b675dda88Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.159.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+26 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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.

References

Show all references (5 more)

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

All records