CVE-2023-53667

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-10-07. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize

Currently in cdc_ncm_check_tx_max(), if dwNtbOutMaxSize is lower than the calculated "min" value, but greater than zero, the logic sets tx_max to dwNtbOutMaxSize. This is then used to allocate a new SKB in cdc_ncm_fill_tx_frame() where all the data is handled.

For small values of dwNtbOutMaxSize the memory allocated during alloc_skb(dwNtbOutMaxSize, GFP_ATOMIC) will have the same size, due to how size is aligned at alloc time: size = SKB_DATA_ALIGN(size); size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); Thus we hit the same bug that we tried to squash with commit 2be6d4d16a084 ("net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero")

Low values of dwNtbOutMaxSize do not cause an issue presently because at alloc_skb() time more memory (512b) is allocated than required for the SKB headers alone (320b), leaving some space (512b - 320b = 192b) for CDC data (172b).

However, if more elements (for example 3 x u64 = [24b]) were added to one of the SKB header structs, say 'struct skb_shared_info', increasing its original size (320b [320b aligned]) to something larger (344b [384b aligned]), then suddenly the CDC data (172b) no longer fits in the spare SKB data area (512b - 384b = 128b).

Consequently the SKB bounds checking semantics fails and panics:

skbuff: skb_over_panic: text:ffffffff831f755b len:184 put:172 head:ffff88811f1c6c00 data:ffff88811f1c6c00 tail:0xb8 end:0x80 dev: ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:113! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 57 Comm: kworker/0:2 Not tainted 5.15.106-syzkaller-00249-g19c0ed55a470 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic net/core/skbuff.c:113 [inline] RIP: 0010:skb_over_panic+0x14c/0x150 net/core/skbuff.c:118 [snip] Call Trace: skb_put+0x151/0x210 net/core/skbuff.c:2047 skb_put_zero include/linux/skbuff.h:2422 [inline] cdc_ncm_ndp16 drivers/net/usb/cdc_ncm.c:1131 [inline] cdc_ncm_fill_tx_frame+0x11ab/0x3da0 drivers/net/usb/cdc_ncm.c:1308 cdc_ncm_tx_fixup+0xa3/0x100

Deal with too low values of dwNtbOutMaxSize, clamp it in the range [USB_CDC_NCM_NTB_MIN_OUT_SIZE, CDC_NCM_NTB_MAX_SIZE_TX]. We ensure enough data space is allocated to handle CDC data by making sure dwNtbOutMaxSize is not smaller than USB_CDC_NCM_NTB_MIN_OUT_SIZE.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

October 7, 2025

Last Modified

February 26, 2026

References (8)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 4.14.317—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.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-28 15:34 UTCEPSS rescore
  2. 2026-07-28 15:34 UTCEPSS rescore
  3. 2026-07-24 14:16 UTCEPSS rescore
  4. 2026-07-23 18:11 UTCOSV refresh
  5. 2026-07-23 14:16 UTCEPSS rescore
  6. 2026-07-23 02:29 UTCEG score recompute
  7. 2026-07-22 23:16 UTCEG score recompute
  8. 2026-07-22 14:07 UTCEPSS rescore
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  1. 2026-07-08 15:13 UTCEPSS rescore
  2. 2026-07-07 13:45 UTCEPSS rescore
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  4. 2026-07-06 16:26 UTCEPSS rescore
  5. 2026-07-06 16:26 UTCEPSS rescore
  6. 2026-07-06 12:41 UTCOSV refresh
  7. 2026-07-06 02:22 UTCEPSS rescore
  8. 2026-07-06 02:22 UTCEPSS rescore
  9. 2026-07-05 02:29 UTCEPSS rescore
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  11. 2026-07-01 15:05 UTCEPSS rescore
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  18. 2026-06-27 03:07 UTCEPSS rescore
  19. 2026-06-25 13:48 UTCEPSS rescore
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  23. 2026-06-23 21:31 UTCEPSS rescore
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  27. 2026-06-21 01:58 UTCEPSS rescore
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  29. 2026-06-19 19:24 UTCEPSS rescore
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  31. 2026-06-18 17:51 UTCEPSS rescore
  32. 2026-06-18 00:43 UTCOSV refresh
  33. 2026-06-17 17:51 UTCEPSS rescore
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  40. 2026-06-12 23:11 UTCEPSS rescore
  41. 2026-06-11 13:59 UTCEPSS rescore
  42. 2026-06-10 22:17 UTCEPSS rescore
  43. 2026-06-10 13:21 UTCEPSS rescore
  44. 2026-06-08 14:16 UTCEPSS rescore
  45. 2026-06-08 14:16 UTCEPSS rescore
  46. 2026-06-07 15:24 UTCEPSS rescore
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  48. 2026-06-06 13:46 UTCEPSS rescore
  49. 2026-06-06 13:46 UTCEPSS rescore
  50. 2026-06-05 22:46 UTCEPSS rescore
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  52. 2026-06-04 13:11 UTCEPSS rescore
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  54. 2026-06-02 20:12 UTCEPSS rescore
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  56. 2026-06-01 13:51 UTCEPSS rescore
  57. 2026-05-31 22:30 UTCEPSS rescore
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  59. 2026-05-31 00:15 UTCEPSS rescore
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  61. 2026-05-29 21:16 UTCEG score recompute
  62. 2026-05-29 21:16 UTCGHSA enrichment
  63. 2026-05-29 13:43 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2023-53667?
CVE-2023-53667 is a medium vulnerability published on October 7, 2025. In the Linux kernel, the following vulnerability has been resolved: net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize Currently in cdcncmchecktxmax(), if dwNtbOutMaxSize is lower than the calculated "min" value, but greater than zero, the logic sets tx_max to dwNtbOutMaxSize. This is then…
When was CVE-2023-53667 disclosed?
CVE-2023-53667 was first published in the National Vulnerability Database on October 7, 2025, with the most recent update on February 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-53667 actively exploited?
CVE-2023-53667 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.5% of all scored CVEs.
What is the CVSS score of CVE-2023-53667?
CVE-2023-53667 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2023-53667?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-53667, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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