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NVD / CVE Program· CNA Linux

CVE-2023-53121: tcp: tcp_make_synack() can be called from process context

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: 0.18% (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 442aa78ed70188b21ccd8669738448702c0a3281, 7613cde8c0c1f02a7ec2e1d536c01b65b135fc1c, 77ad58bca0119e8cc3e0e9d91a3f22caa66e4dfa.

Low priority for now. Upgrade to Linux Linux 442aa78ed70188b21ccd8669738448702c0a3281, 7613cde8c0c1f02a7ec2e1d536c01b65b135fc1c, 77ad58bca0119e8cc3e0e9d91a3f22caa66e4dfa 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: 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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 2, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 8th percentile
CWE
—

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

If any of these changes, we'll tell you in the daily email digest.

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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.

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 kernel3.7 and later · before 4.14.311
  • linux linux kernel4.15 and later · before 4.19.279
  • linux linux kernel4.20 and later · before 5.4.238
  • linux linux kernel5.5 and later · before 5.10.176
  • linux linux kernel5.11 and later · before 5.15.104
  • linux linux kernel5.16 and later · before 6.1.21
  • linux linux kernel6.2 and later · before 6.2.8
  • linux linux kernel6.3

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

    • 3.7affected
    • before 3.7not affected · semver
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before d493d4fe88195a144d6a277a90062a7534ed2192affected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before e23ca307745be3df7fe9762f3e2a7e311a57852eaffected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before 442aa78ed70188b21ccd8669738448702c0a3281affected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before 77ad58bca0119e8cc3e0e9d91a3f22caa66e4dfaaffected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before ad07290d63ff6689f50565b02f5b6f34ec15a5caaffected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before 9180aa4622a720b433e842b4d3aa34d73eec577aaffected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before 7613cde8c0c1f02a7ec2e1d536c01b65b135fc1caffected · git
    • 8336886f786fdacbc19b719c1f7ea91eb70706d4 and later · before bced3f7db95ff2e6ca29dc4d1c9751ab5e736a09affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.25-16.1.25-1

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-2023-53119May 2, 2025 · nfc: pn533: initialize struct pn533_out_arg properly
    22Monitor
  • ← EarlierCVE-2023-53120May 2, 2025 · scsi: mpi3mr: Fix config page DMA memory leak
    22Monitor
  • Later →CVE-2023-53123May 2, 2025 · PCI: s390: Fix use-after-free of PCI resources with per-function hotplug
    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 Linux442aa78ed70188b21ccd8669738448702c0a3281Vendor (CNA)
Linux Linux7613cde8c0c1f02a7ec2e1d536c01b65b135fc1cVendor (CNA)
Linux Linux77ad58bca0119e8cc3e0e9d91a3f22caa66e4dfaVendor (CNA)
Linux Linux9180aa4622a720b433e842b4d3aa34d73eec577aVendor (CNA)
Linux Linuxad07290d63ff6689f50565b02f5b6f34ec15a5caVendor (CNA)
Linux Linuxbced3f7db95ff2e6ca29dc4d1c9751ab5e736a09Vendor (CNA)
Linux Linuxd493d4fe88195a144d6a277a90062a7534ed2192Vendor (CNA)
Linux Linuxe23ca307745be3df7fe9762f3e2a7e311a57852eVendor (CNA)
debian:linux6.1.25-1 · 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.

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.

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)

—

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 (7 more)

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

All records