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

CVE-2026-99054: tipc: destroy topsrv workqueues before closing connections

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: 0.15% (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 09dbd610f78aaed65d7b379c270ce4090a8151ac, 0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e, 21622e5ae8b232c2e64eb1adf5546cf078d2987d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 09dbd610f78aaed65d7b379c270ce4090a8151ac, 0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e, 21622e5ae8b232c2e64eb1adf5546cf078d2987d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 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: tipc: destroy topsrv workqueues before closing connections tipc_topsrv_stop() closed subscriber connections while the topology server's send and receive workqueues were still running. Socket callbacks and subscription events could then queue more work, and in-flight send/recv work could drop the last connection reference during the conn_idr walk. That race produced several teardown failures: refcount_t addition on 0 from conn_get() on a connection whose release was blocked on idr_lock, a subsequent use-after-free in tipc_conn_close(), queue_work() on an already destroyed workqueue from the listener data-ready callback, and an RCU stall in tipc_topsrv_exit_net() while the walk spun under idr_lock. Clear srv->listener under idr_lock so it acts as a shutdown flag, skip queue_work() once it is NULL, destroy the workqueues to flush in-flight work, and only then close the remaining connections. Refuse tipc_conn_lookup() after that flag is cleared, and drop idr_lock when the teardown walk finds no connection, so an in-flight subscription event cannot pin idr_in_use while the walk holds the lock. v3 supersedes the narrower in-thread diff Tung Quang Nguyen posted on 2026-09-23. It keeps his teardown order and adds the lookup refusal and the empty-idr unlock.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 23, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 5th 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%

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.

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  • No public exploit code on record
  • 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.

—

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

    • 3.11affected
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 09dbd610f78aaed65d7b379c270ce4090a8151acaffected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 21622e5ae8b232c2e64eb1adf5546cf078d2987daffected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 7167afaaaee37191f8b6afa0c91e0fef41460705affected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 7f796bb3b440d7f1b14c0e3b520462eb34f553afaffected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before da9c16568bc79140a54c1f5fcf07a0305df47b37affected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 0af8780bdfdfc91fb9127bddb9c48fab67dc9d9eaffected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before fb717c536af2aafeca520ff11d1e0f25f7ab8fa9affected · git
    • c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and later · before 3acdd44385bc7e2e57605e073691ce69cc5a960daffected · git
    • before 3.11not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.11-17.2.11-1

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-2026-99052Oct 23, 2026 · selinux: preserve NATIVE_LABELS on already-initialized sb in set_mnt_opts
    0Monitor
  • ← EarlierCVE-2026-99053Oct 23, 2026 · tipc: hold a reference to nodes found by link name
    31Monitor
  • Later →CVE-2026-99055Oct 23, 2026 · tcp: reject net_iov in zerocopy receive mapping hints
    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 Linux09dbd610f78aaed65d7b379c270ce4090a8151acVendor (CNA)
Linux Linux0af8780bdfdfc91fb9127bddb9c48fab67dc9d9eVendor (CNA)
Linux Linux21622e5ae8b232c2e64eb1adf5546cf078d2987dVendor (CNA)
Linux Linux3acdd44385bc7e2e57605e073691ce69cc5a960dVendor (CNA)
Linux Linux7167afaaaee37191f8b6afa0c91e0fef41460705Vendor (CNA)
Linux Linux7f796bb3b440d7f1b14c0e3b520462eb34f553afVendor (CNA)
Linux Linuxda9c16568bc79140a54c1f5fcf07a0305df47b37Vendor (CNA)
Linux Linuxfb717c536af2aafeca520ff11d1e0f25f7ab8fa9Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package 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. TodayOct 31, 2026+8 d
EPSS, last 120 days

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

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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
high · data or configuration can be modified
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
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/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. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

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

References

Show all references (4 more)

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

All records