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Linux KernelOperating system · Linux

CVE-2023-53121

MEDIUM · 5.5 CVSS v3.1 Published 2025-05-02
Fix available
A fix is available. Upgrade to 4.14.311 / 4.19.279 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: tcp: tcp_make_synack() can be called from process context tcp_rtx_synack() now could be called in process context as explained in 0a375c822497 ("tcp: tcp_rtx_synack() can be called from process context"). tcp_rtx_synack() might call tcp_make_synack(), which will touch per-CPU variables with preemption enabled. This causes the following BUG: BUG: using __this_cpu_add() in preemptible [00000000] code: ThriftIO1/5464 caller is tcp_make_synack+0x841/0xac0 Call Trace: <TASK> dump_stack_lvl+0x10d/0x1a0 check_preemption_disabled+0x104/0x110 tcp_make_synack+0x841/0xac0 tcp_v6_send_synack+0x5c/0x450 tcp_rtx_synack+0xeb/0x1f0 inet_rtx_syn_ack+0x34/0x60 tcp_check_req+0x3af/0x9e0 tcp_rcv_state_process+0x59b/0x2030 tcp_v6_do_rcv+0x5f5/0x700 release_sock+0x3a/0xf0 tcp_sendmsg+0x33/0x40 ____sys_sendmsg+0x2f2/0x490 __sys_sendmsg+0x184/0x230 do_syscall_64+0x3d/0x90 Avoid calling __TCP_INC_STATS() with will touch per-cpu variables. Use TCP_INC_STATS() which is safe to be called from context switch.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 3.7, < 4.14.311>= 4.15, < 4.19.279>= 4.20, < 5.4.238>= 5.5, < 5.10.176>= 5.11, < 5.15.104>= 5.16, < 6.1.21>= 6.2, < 6.2.8= 6.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.14.311 / 4.19.279 / 5.4.238 or later
Fixed in 4.14.3114.19.2795.4.238
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel 4.14.311+ (for 4.14 branch), 4.19.279+ (for 4.19 branch), 5.4.238+ (for 5.4 branch), or 5.10.176+ (for 5.10 branch)

  1. Identify the current kernel version using `uname -r`
  2. Determine which version branch your kernel is on (e.g., 4.14.x, 4.19.x, 5.4.x, or 5.10.x)
  3. Upgrade the Linux kernel to a version >= 4.14.311, 4.19.279, 5.4.238, or 5.10.176 depending on your branch
  4. Reboot the system to load the fixed kernel
  5. Verify the fix is applied by checking the kernel version and reviewing the commit 442aa78ed70188b21ccd8669738448702c0a3281 is included
Caveat Kernel upgrades may require rebooting and could have compatibility implications with custom modules or specific hardware drivers

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-53121 in production — separate from our analysis above.

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What this is

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