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CVE-2026-68397· NVD / CVE Program· CNA Linux

net/iucv: take a reference on the socket found in afiucv_hs_rcv()

Noroxi assessment

Priority: Monitor (action score 35/100)

  • 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: 0.26% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1801cb20a5025a787d6853e19c38db138344b4b4, 4dc0e63abf8bc7ba8892e617c1fb8b204361e022, 4fa349156043dc119721d067329714179f501749; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1801cb20a5025a787d6853e19c38db138344b4b4, 4dc0e63abf8bc7ba8892e617c1fb8b204361e022, 4fa349156043dc119721d067329714179f501749; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 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: net/iucv: take a reference on the socket found in afiucv_hs_rcv() afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock, drops the lock, and then passes the socket to the afiucv_hs_callback_*() handlers without holding a reference. AF_IUCV sockets are not RCU-protected and are freed synchronously by iucv_sock_kill() -> sock_put(), so a concurrent close can free the socket in the window between read_unlock() and the handler, which then dereferences freed memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()). Take a reference with sock_hold() while the socket is still on the list and release it with sock_put() once the handler has run.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Aug 10, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 17th percentile

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.8
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.

Follow CVE-2026-68397

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

    • 3.2affected
    • 3881ac441f642d56503818123446f7298442236b and later · before 5739be5c19495d709d902a2912c9102ce78740d5affected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before bc6c6e546ffff8865daaeb622ef348c2d481e80faffected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before e3e0679fc950191aff8f27fa78abcfc2462cff4aaffected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before 4dc0e63abf8bc7ba8892e617c1fb8b204361e022affected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before 1801cb20a5025a787d6853e19c38db138344b4b4affected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before c75a950e77356e526672cba4584080c6c8b793b6affected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before 5595ea59cdf29182cf6a270cacc1426c57b603deaffected · git
    • 3881ac441f642d56503818123446f7298442236b and later · before 4fa349156043dc119721d067329714179f501749affected · git
    • before 3.2not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.101-1~deb12u16.12.101-1~deb12u1
Debian:13linuxbefore 6.12.101-16.12.101-1
Debian:14linuxbefore 7.1.6-17.1.6-1

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-2026-68394Aug 10, 2026 · Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update
    31Monitor
  • ← EarlierCVE-2026-68396Aug 10, 2026 · scsi: core: wake eh reliably when using scsi_schedule_eh
    0Monitor
  • Later →CVE-2026-68398Aug 10, 2026 · ppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF
    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 Linux1801cb20a5025a787d6853e19c38db138344b4b4Vendor (CNA)
Linux Linux4dc0e63abf8bc7ba8892e617c1fb8b204361e022Vendor (CNA)
Linux Linux4fa349156043dc119721d067329714179f501749Vendor (CNA)
Linux Linux5595ea59cdf29182cf6a270cacc1426c57b603deVendor (CNA)
Linux Linux5739be5c19495d709d902a2912c9102ce78740d5Vendor (CNA)
Linux Linuxbc6c6e546ffff8865daaeb622ef348c2d481e80fVendor (CNA)
Linux Linuxc75a950e77356e526672cba4584080c6c8b793b6Vendor (CNA)
Linux Linuxe3e0679fc950191aff8f27fa78abcfc2462cff4aVendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.101-1~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.

No dated events beyond publication.

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.

  • CVE-2026-681170 days aparttipc: clear sock->sk on the failed-insert path in tipc_sk_create()
    39Monitor
  • CVE-2026-681270 days apartila: reload IPv6 header after pskb_may_pull in checksum adjust
    39Monitor
  • CVE-2026-681440 days apartphonet: pep: fix use-after-free in pep_get_sb()
    39Monitor
  • CVE-2026-681560 days apartlibceph: refresh auth->authorizer_buf{,_len} after authorizer update
    39Monitor
  • CVE-2026-683810 days apartksmbd: pin conn during async oplock break notification
    39Monitor
  • CVE-2026-684260 days apartxfrm: fix stale skb->prev after async crypto steals a GSO segment
    39Monitor

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 on the same network segment 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
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

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