CVE-2023-53781

HIGHPre-NVD 7.87.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-12-09. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2023-60125 (ENISA EUVD) · GHSA-3h9m-xfjq-9f2f (GitHub Security Advisories)Source: ENISA EUVD

7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

smc: Fix use-after-free in tcp_write_timer_handler().

With Eric's ref tracker, syzbot finally found a repro for use-after-free in tcp_write_timer_handler() by kernel TCP sockets. [0]

If SMC creates a kernel socket in __smc_create(), the kernel socket is supposed to be freed in smc_clcsock_release() by calling sock_release() when we close() the parent SMC socket.

However, at the end of smc_clcsock_release(), the kernel socket's sk_state might not be TCP_CLOSE. This means that we have not called inet_csk_destroy_sock() in __tcp_close() and have not stopped the TCP timers.

The kernel socket's TCP timers can be fired later, so we need to hold a refcnt for net as we do for MPTCP subflows in mptcp_subflow_create_socket().

[0]: leaked reference. sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108) inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244) __sock_create (net/socket.c:1546) smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284) __sock_create (net/socket.c:1546) __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661) __x64_sys_socket (net/socket.c:1672) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) ================================================================== BUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) Read of size 1 at addr ffff888052b65e0d by task syzrepro/18091

CPU: 0 PID: 18091 Comm: syzrepro Tainted: G W 6.3.0-rc4-01174-gb5d54eb5899a #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:107) print_report (mm/kasan/report.c:320 mm/kasan/report.c:430) kasan_report (mm/kasan/report.c:538) tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643) call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701) __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022) run_timer_softirq (kernel/time/timer.c:2037) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572) __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650) irq_exit_rcu (kernel/softirq.c:664) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-11). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

December 9, 2025

Last Modified

October 30, 2026

Advisory Details (2)

Auto-updated Aug 5, 2026
Patch available.
Web page

smc: Fix use-after-free in tcp_write_timer_handler(). - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9744d2bf19762703704ecba885b7ac282c02eacf
Web page

smc: Fix use-after-free in tcp_write_timer_handler(). - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1cc41c8acfc1ee30b4868559058db97fa44b0137

Vendor Advisories for CVE-2023-53781(7)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatkernel-0:4.18.0-477.172.1.el8_82026-10-07redhat
redhatkernel-0:4.18.0-305.208.1.el8_42026-09-22redhat
redhatkernel-0:4.18.0-372.216.1.el8_62026-09-22redhat
redhatkernel-rt-0:4.18.0-553.132.1.rt7.473.el8_102026-06-10redhat
redhatkernel-0:4.18.0-553.132.1.el8_102026-06-10redhat
redhatkernel-0:5.14.0-611.5.1.el9_72025-11-11redhat
linuxKernel @ 6.2.12 (fixes >=4.11.0)—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (498 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.3~rc7-1~exp1 (371 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.3.7-1: fixed in 6.3.7-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.3.7-1: fixed in 6.3.7-1
—

Data Freshness Timeline

(refreshed 9× in last 7d / 45× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 271 rows on record for this CVE, as 95 entries (5 repeats merged).

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 171 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:45 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-11-12 16:30 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-11-12 06:30 UTCEchelonGraph re-scored
  4. 2026-11-12 06:30 UTCVendor advisory
  5. 2026-11-12 06:30 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  6. 2026-11-11 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  7. 2026-11-10 16:37 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-11-09 16:30 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-11-08 16:35 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  10. 2026-11-07 16:35 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  11. 2026-11-06 16:31 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  12. 2026-11-05 21:58 UTCEchelonGraph re-scored
  13. 2026-11-05 21:58 UTCVendor advisory
  14. 2026-11-05 21:58 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  15. 2026-11-05 16:33 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  16. 2026-11-04 16:31 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  17. 2026-11-03 16:41 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  18. 2026-11-02 16:40 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  19. 2026-11-01 16:31 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  20. 2026-10-31 16:30 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  21. 2026-10-30 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  22. 2026-10-30 13:26 UTCEchelonGraph re-scored
  23. 2026-10-30 13:26 UTCVendor advisory
  24. 2026-10-30 13:26 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  25. 2026-10-30 12:31 UTCEchelonGraph re-scored
Show 70 more
  1. 2026-10-30 12:31 UTCVendor advisory
  2. 2026-10-30 12:31 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  3. 2026-10-29 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  4. 2026-10-28 22:42 UTCEchelonGraph re-scored
  5. 2026-10-28 22:42 UTCVendor advisory
  6. 2026-10-28 22:42 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  7. 2026-10-28 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  8. 2026-10-26 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  9. 2026-10-25 17:27 UTCEchelonGraph re-scored
  10. 2026-10-25 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  11. 2026-10-24 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  12. 2026-10-23 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  13. 2026-10-22 16:31 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  14. 2026-10-22 07:09 UTCEchelonGraph re-scored
  15. 2026-10-22 07:09 UTCVendor advisory
  16. 2026-10-22 07:09 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  17. 2026-10-21 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  18. 2026-10-20 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  19. 2026-10-19 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  20. 2026-10-18 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  21. 2026-10-18 07:40 UTCEchelonGraph re-scored
  22. 2026-10-17 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  23. 2026-10-16 16:36 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  24. 2026-10-15 22:37 UTCEchelonGraph re-scored
  25. 2026-10-15 22:37 UTCVendor advisory
  26. 2026-10-15 22:37 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  27. 2026-10-15 21:56 UTCEchelonGraph re-scored
  28. 2026-10-15 21:56 UTCVendor advisory
  29. 2026-10-15 21:56 UTCGHSA enrichmentGHSA-3h9m-xfjq-9f2f · GitHub severity HIGH · GitHub CVSS 7.8
  30. 2026-10-15 16:29 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  31. 2026-10-14 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  32. 2026-10-13 16:30 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  33. 2026-10-12 18:12 UTCEchelonGraph re-scored
  34. 2026-10-11 21:37 UTCEchelonGraph re-scored
  35. 2026-10-11 13:45 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  36. 2026-10-10 19:58 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  37. 2026-10-09 20:05 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  38. 2026-10-08 17:06 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  39. 2026-10-07 23:46 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  40. 2026-10-06 15:15 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  41. 2026-10-05 17:41 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  42. 2026-10-04 23:20 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  43. 2026-10-03 14:23 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  44. 2026-10-01 19:48 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  45. 2026-10-01 04:10 UTCOSV refresh
  46. 2026-09-30 16:37 UTCEchelonGraph re-scored
  47. 2026-09-30 15:01 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  48. 2026-09-29 15:17 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  49. 2026-09-28 13:49 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  50. 2026-09-26 00:22 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  51. 2026-09-24 14:01 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  52. 2026-09-23 13:46 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  53. 2026-09-20 20:14 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  54. 2026-09-18 19:26 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  55. 2026-09-16 14:06 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  56. 2026-09-16 05:11 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  57. 2026-09-15 03:08 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  58. 2026-09-13 16:45 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  59. 2026-09-12 14:58 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  60. 2026-09-12 06:40 UTCOSV refresh
  61. 2026-09-11 14:51 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  62. 2026-09-11 09:34 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  63. 2026-09-08 21:58 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  64. 2026-09-07 15:59 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  65. 2026-09-06 13:46 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  66. 2026-09-05 15:26 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  67. 2026-09-04 13:58 UTCEPSS rescoreEPSS 0.1% · 4th percentile
  68. 2026-09-04 05:04 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  69. 2026-09-01 13:52 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  70. 2026-09-01 04:36 UTCEPSS rescoreEPSS 0.1% · 3rd percentile

Related CVEs(same vendor)

Frequently asked(5)

What is CVE-2023-53781?
CVE-2023-53781 is a high-severity vulnerability; its CVE record was published on December 9, 2025. In the Linux kernel, the following vulnerability has been resolved: smc: Fix use-after-free in tcp_write_timer_handler(). With Eric's ref tracker, syzbot finally found a repro for use-after-free in tcp_write_timer_handler() by kernel TCP sockets. [0] If SMC creates a kernel socket in…
When was the CVE record for CVE-2023-53781 published?
The CVE record for CVE-2023-53781 was published on December 9, 2025. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 30, 2026; the record at its source may have been updated since.
Is CVE-2023-53781 actively exploited?
CVE-2023-53781 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2023-53781?
CVE-2023-53781 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2023-53781?
A fix for CVE-2023-53781 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2023-53781 are linked in the Vendor Advisories panel on this page.

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