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CVE Record

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

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

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel concurrency bug in UNIX domain socket file-descriptor handling. The public record shows a data race detected by KCSAN and fixed in stable kernel commits. The sources do not state a proven security impact, CVSS score, or active exploitation, so urgency depends on whether exposed systems run affected kernel builds.

Executive priority

Treat this as a kernel maintenance priority, not an emergency, unless a vendor rates your platform higher. Patch through normal Linux update cycles, with extra attention to shared compute environments.

Technical view

The race involves user->unix_inflight in af_unix. Writes occur under unix_gc_lock, while too_many_unix_fds() read it locklessly. The fix annotates read/write accesses around unix_inflight. The trace involves sendmsg paths for UNIX datagram and seqpacket sockets carrying file descriptors.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions or downstream builds that have not incorporated the referenced stable fixes. The bundle lists Linux as affected, including version ranges around 4.5 through 6.6 and stable branch fix references.

Exploitation context

No cited source reports exploitation, and the CVE is not marked KEV. The public material describes a sanitizer-detected race, not a demonstrated exploit path. Practical impact is unclear from the provided evidence.

Researcher notes

The strongest evidence is the kernel commit narrative and KCSAN report. The bundle does not provide CVSS, CWE, exploitability assessment, or a user-visible impact. Avoid inferring privilege escalation, denial of service, or information disclosure without additional vendor analysis.

Mitigation direction

  • Check vendor kernel advisories for CVE-2023-53204 applicability.
  • Apply kernel updates that include the referenced stable commits.
  • Prioritize multi-user, container, and shared-host Linux systems for review.
  • Track downstream distribution backports, not only upstream version numbers.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and images.
  • Confirm whether vendor builds include the af_unix unix_inflight fix.
  • Review kernel changelogs for the referenced stable commit IDs.
  • Document systems deferred from patching and compensating controls used.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2023-53204 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
9Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, 712f4aad406bb1ed67f3f98d04c044191f0ff593, a5a6cf8c405e826ff7ed1308dde72560c0ed4854, df87da0783c4492b944badfea9d5c3c56b834697, 3d024dcef2548028e9f9b7876a544e6e0af00175, aa51d1c24ec3b6605f7cc7ef500c96cd71d7ef90, a5b9e44af8d3edaf49d14a91cc519a9fba439e67, dc6b0ec667f67d4768e72c1b7f1bbc14ea52379c, 9b8b611fe0f86f07a4ff4a5f3bcb0ea7ceb7da3b, 5e226f9689d90ad8ab21b4a969ae3058777f0affunaffected
LinuxLinux4.5, 0, 4.14.326, 4.19.295, 5.4.257, 5.10.195, 5.15.132, 6.1.54, 6.5.4, 6.6affected
Weakness

CWE details

No CWE listed

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