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NVD / CVE Program· CNA Linux

CVE-2026-53181: vsock/vmci: fix sk_ack_backlog leak on failed handshake

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: 0.12% (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 22c587aa3ab1ab5264daff3ec32136fd30436c13, 9698582a4dd9c4a05889d7db96d4c0edc9e69cac, ba9ad6015937a5e46ba1a31370e3efdec8abbdcc; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1.

Low priority for now. Upgrade to Linux Linux 22c587aa3ab1ab5264daff3ec32136fd30436c13, 9698582a4dd9c4a05889d7db96d4c0edc9e69cac, ba9ad6015937a5e46ba1a31370e3efdec8abbdcc; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1 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: vsock/vmci: fix sk_ack_backlog leak on failed handshake When vmci_transport_recv_connecting_server() returns an error, vmci_transport_recv_listen() calls vsock_remove_pending() but never calls sk_acceptq_removed(). This leaves sk_ack_backlog incremented permanently. Repeated handshake failures (malformed packets, queue pair alloc failure, event subscribe failure) cause sk_ack_backlog to climb toward sk_max_ack_backlog. Once it reaches the limit the listener permanently refuses all new connections with -ECONNREFUSED, a silent denial of service requiring a process restart to recover. The two existing sk_acceptq_removed() calls in af_vsock.c do not cover this path: line 764 checks vsock_is_pending() which returns false after vsock_remove_pending(), and line 1889 is only reached on successful accept(). Fix by balancing sk_acceptq_added() with sk_acceptq_removed() on the error path.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 25, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 2th 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%

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

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When you'll hear from us

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  • 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.

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 kernel3.9 and later · before 5.10.259
  • linux linux kernel5.11 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.143
  • linux linux kernel6.7 and later · before 6.12.94
  • linux linux kernel6.13 and later · before 6.18.36
  • linux linux kernel6.19 and later · before 7.0.13
  • linux linux kernel7.1

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

    • 3.9affected
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before 22c587aa3ab1ab5264daff3ec32136fd30436c13affected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before cf7090e255d74c4b61c51f8ede9fcacdd8393b5baffected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before ea0b03d52881c12a8c634ea0d6cbfa61cefdb488affected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before dfd853197615d322d3a88dbcab91fc0fd2096219affected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before bcb275626055df7f8f947f1a349754b4004d9a15affected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before ba9ad6015937a5e46ba1a31370e3efdec8abbdccaffected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before 9698582a4dd9c4a05889d7db96d4c0edc9e69cacaffected · git
    • d021c344051af91f42c5ba9fdedc176740cbd238 and later · before c05fa14db43ebef3bd862ca9d073981c0358b3f0affected · git
    • before 3.9not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.13-17.0.13-1

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-2026-53179Jun 25, 2026 · staging: rtl8723bs: fix buffer over-read in rtw_update_protection
    28Monitor
  • ← EarlierCVE-2026-53180Jun 25, 2026 · timers/migration: Fix livelock in tmigr_handle_remote_up()
    30Monitor
  • Later →CVE-2026-53182Jun 25, 2026 · wifi: nl80211: reject oversized EMA RNR lists
    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 Linux22c587aa3ab1ab5264daff3ec32136fd30436c13Vendor (CNA)
Linux Linux9698582a4dd9c4a05889d7db96d4c0edc9e69cacVendor (CNA)
Linux Linuxba9ad6015937a5e46ba1a31370e3efdec8abbdccVendor (CNA)
Linux Linuxbcb275626055df7f8f947f1a349754b4004d9a15Vendor (CNA)
Linux Linuxc05fa14db43ebef3bd862ca9d073981c0358b3f0Vendor (CNA)
Linux Linuxcf7090e255d74c4b61c51f8ede9fcacdd8393b5bVendor (CNA)
Linux Linuxdfd853197615d322d3a88dbcab91fc0fd2096219Vendor (CNA)
Linux Linuxea0b03d52881c12a8c634ea0d6cbfa61cefdb488Vendor (CNA)
azl3 kernel 6.6.141.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.176-1 · 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.

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

  • 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-401 · Missing Release of Memory after Effective Lifetime

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 (8 more)

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

All records