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NVD / CVE Program· CNA Linux

CVE-2023-53204: af_unix: Fix data-races around user->unix_inflight.

Noroxi assessment

Priority: Monitor (action score 18/100)

  • 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: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 03d133dfbcec9d439729cc64706c7eb6d1663a24, 0bc36c0650b21df36fbec8136add83936eaf0607, 3.11.

Low priority for now. Upgrade to Linux Linux 03d133dfbcec9d439729cc64706c7eb6d1663a24, 0bc36c0650b21df36fbec8136add83936eaf0607, 3.11 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: af_unix: Fix data-races around user->unix_inflight. user->unix_inflight is changed under spin_lock(unix_gc_lock), but too_many_unix_fds() reads it locklessly. Let's annotate the write/read accesses to user->unix_inflight. BUG: KCSAN: data-race in unix_attach_fds / unix_inflight write to 0xffffffff8546f2d0 of 8 bytes by task 44798 on cpu 1: unix_inflight+0x157/0x180 net/unix/scm.c:66 unix_attach_fds+0x147/0x1e0 net/unix/scm.c:123 unix_scm_to_skb net/unix/af_unix.c:1827 [inline] unix_dgram_sendmsg+0x46a/0x14f0 net/unix/af_unix.c:1950 unix_seqpacket_sendmsg net/unix/af_unix.c:2308 [inline] unix_seqpacket_sendmsg+0xba/0x130 net/unix/af_unix.c:2292 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0x148/0x160 net/socket.c:748 ____sys_sendmsg+0x4e4/0x610 net/socket.c:2494 ___sys_sendmsg+0xc6/0x140 net/socket.c:2548 __sys_sendmsg+0x94/0x140 net/socket.c:2577 __do_sys_sendmsg net/socket.c:2586 [inline] __se_sys_sendmsg net/socket.c:2584 [inline] __x64_sys_sendmsg+0x45/0x50 net/socket.c:2584 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 read to 0xffffffff8546f2d0 of 8 bytes by task 44814 on cpu 0: too_many_unix_fds net/unix/scm.c:101 [inline] unix_attach_fds+0x54/0x1e0 net/unix/scm.c:110 unix_scm_to_skb net/unix/af_unix.c:1827 [inline] unix_dgram_sendmsg+0x46a/0x14f0 net/unix/af_unix.c:1950 unix_seqpacket_sendmsg net/unix/af_unix.c:2308 [inline] unix_seqpacket_sendmsg+0xba/0x130 net/unix/af_unix.c:2292 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0x148/0x160 net/socket.c:748 ____sys_sendmsg+0x4e4/0x610 net/socket.c:2494 ___sys_sendmsg+0xc6/0x140 net/socket.c:2548 __sys_sendmsg+0x94/0x140 net/socket.c:2577 __do_sys_sendmsg net/socket.c:2586 [inline] __se_sys_sendmsg net/socket.c:2584 [inline] __x64_sys_sendmsg+0x45/0x50 net/socket.c:2584 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 value changed: 0x000000000000000c -> 0x000000000000000d Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 44814 Comm: systemd-coredum Not tainted 6.4.0-11989-g6843306689af #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Sep 15, 2025
Updated
Nov 5, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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.

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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 kernel3.2.78 and later · before 3.3
  • linux linux kernel3.10.96 and later · before 3.11
  • linux linux kernel3.12.57 and later · before 3.13
  • linux linux kernel3.14.60 and later · before 3.15
  • linux linux kernel3.18.27 and later · before 3.19
  • linux linux kernel4.1.17 and later · before 4.2
  • linux linux kernel4.3.5 and later · before 4.4
  • linux linux kernel4.4.1 and later · before 4.14.326
  • linux linux kernel4.15 and later · before 4.19.295
  • linux linux kernel4.20 and later · before 5.4.257
  • linux linux kernel5.5 and later · before 5.10.195
  • linux linux kernel5.11 and later · before 5.15.132
  • linux linux kernel5.16 and later · before 6.1.54
  • linux linux kernel6.2 and later · before 6.5.4

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

    • a5a6cf8c405e826ff7ed1308dde72560c0ed4854, df87da0783c4492b944badfea9d5c3c56b834697, 3d024dcef2548028e9f9b7876a544e6e0af00175, aa51d1c24ec3b6605f7cc7ef500c96cd71d7ef90, a5b9e44af8d3edaf49d14a91cc519a9fba439e67, dc6b0ec667f67d4768e72c1b7f1bbc14ea52379c, 9b8b611fe0f86f07a4ff4a5f3bcb0ea7ceb7da3b, 5e226f9689d90ad8ab21b4a969ae3058777f0aff, 4.5affected
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before df97b5ea9f3ac9308c3a633524dab382cd59d9e5affected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before 03d133dfbcec9d439729cc64706c7eb6d1663a24affected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before adcf4e069358cdee8593663650ea447215a1c49eaffected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before b401d7e485b0a234cf8fe9a6ae99dbcd20863138affected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before 9151ed4b006125cba7c06c79df504340ea4e9386affected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before b9cdbb38e030fc2fe97fe27b54cbb6b4fbff250faffected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before ac92f239a079678a035c0faad9089354a874aedeaffected · git
    • 712f4aad406bb1ed67f3f98d04c044191f0ff593 and later · before 0bc36c0650b21df36fbec8136add83936eaf0607affected · git
    • 3.2.78 and later · before 3.3affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.55-16.1.55-1
Debian:13linuxbefore 6.5.6-16.5.6-1

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-2023-53200Sep 15, 2025 · netfilter: x_tables: fix percpu counter block leak on error path when creating new netns
    22Monitor
  • ← EarlierCVE-2023-53201Sep 15, 2025 · RDMA/bnxt_re: wraparound mbox producer index
    22Monitor
  • Later →CVE-2023-53205Sep 15, 2025 · KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler
    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 Linux03d133dfbcec9d439729cc64706c7eb6d1663a24Vendor (CNA)
Linux Linux0bc36c0650b21df36fbec8136add83936eaf0607Vendor (CNA)
Linux Linux3.11Vendor (CNA)
Linux Linux3.13Vendor (CNA)
Linux Linux3.15Vendor (CNA)
Linux Linux3.19Vendor (CNA)
Linux Linux3.3Vendor (CNA)
Linux Linux4.2Vendor (CNA)
Linux Linux4.4Vendor (CNA)
Linux Linux4.5Vendor (CNA)
Linux Linux9151ed4b006125cba7c06c79df504340ea4e9386Vendor (CNA)
Linux Linuxac92f239a079678a035c0faad9089354a874aedeVendor (CNA)
Linux Linuxadcf4e069358cdee8593663650ea447215a1c49eVendor (CNA)
Linux Linuxb401d7e485b0a234cf8fe9a6ae99dbcd20863138Vendor (CNA)
Linux Linuxb9cdbb38e030fc2fe97fe27b54cbb6b4fbff250fVendor (CNA)
Linux Linuxdf97b5ea9f3ac9308c3a633524dab382cd59d9e5Vendor (CNA)
debian:linux6.1.55-1 · 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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:L/AC:H/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.

ATT&CK techniques

—

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