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TI-2023-29421 Aliases CVE-2023-53121GHSA-cwj5-qqpc-pw3v

tcp: tcp_make_synack() can be called from process context

Priority LOW 24Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 4 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00189 8th percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.14.311, 4.19.279, 5.4.238 +5Red Hat: 1 advisoryRed Hat: 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux3.7 and later4.14.311, 4.19.279, 5.4.238, 5.10.176, 5.15.104, 6.1.21, 6.2.8, 6.3Patch availableCNA
  • Linux VendorLinux Affected 3.7 and later Fixed in 4.14.311, 4.19.279, 5.4.238, 5.10.176, 5.15.104, 6.1.21, 6.2.8, 6.3 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.7 to before 4.14.311; 4.15 to before 4.19.279; 4.20 to before 5.4.238; 5.5 to before 5.10.176; 5.11 to before 5.15.104; 5.16 to before 6.1.21; 6.2 to before 6.2.8VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.3:rc1:*:*:*:*:*:*6.3 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.3:rc2:*:*:*:*:*:*6.3 rc2VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.7 to before 4.14.311; 4.15 to before 4.19.279; 4.20 to before 5.4.238; 5.5 to before 5.10.176; 5.11 to before 5.15.104; 5.16 to before 6.1.21; 6.2 to before 6.2.8 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.3:rc1:*:*:*:*:*:* Versions 6.3 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.3:rc2:*:*:*:*:*:* Versions 6.3 rc2 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 4.14.311, 4.19.279, 5.4.238, 5.10.176, 5.15.104, 6.1.21, 6.2.8, 6.3

Red Hat 1 advisory

  • RHSA-2023:6583 Released 2023-11-07 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-362.8.1.el9_3, libperf-5.14.0-362.8.1.el9_3
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-362.8.1.el9_3, kernel-64k-debug-devel-matched-5.14.0-362.8.1.el9_3, kernel-64k-devel-5.14.0-362.8.1.el9_3 +11
    • Red Hat Enterprise Linux BaseOS (v. 9) bpftool-7.2.0-362.8.1.el9_3, kernel-5.14.0-362.8.1.el9_3, kernel-64k-5.14.0-362.8.1.el9_3 +29
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-362.8.1.el9_3, kernel-rt-core-5.14.0-362.8.1.el9_3, kernel-rt-debug-5.14.0-362.8.1.el9_3 +9
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-362.8.1.el9_3, kernel-rt-core-5.14.0-362.8.1.el9_3, kernel-rt-debug-5.14.0-362.8.1.el9_3 +11

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Not affected: 1 product
  • Red Hat Enterprise Linux 10

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-53121
  2. 2026-10-03 Alias added: GHSA-cwj5-qqpc-pw3v
  3. 2026-11-05 CISA SSVC decision points changed

References

Patch 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences