CVE-2026-53306

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-06-26. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 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

A fix is available — apply it.

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

tty: hvc_iucv: fix off-by-one in number of supported devices

MAX_HVC_IUCV_LINES == HVC_ALLOC_TTY_ADAPTERS == 8. This is the number of entries in: static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];

Sometimes hvc_iucv_table[] is limited by: (a) if (num > hvc_iucv_devices) // for error detection or (b) for (i = 0; i < hvc_iucv_devices; i++) // in 2 places (so these 2 don't agree; second one appears to be correct to me.)

hvc_iucv_devices can be 0..8. This is a counter. (c) if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)

If hvc_iucv_devices == 8, (a) allows the code to access hvc_iucv_table[8]. Oops.

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
2%
KEV
Not listed

Published

June 26, 2026

Last Modified

July 6, 2026

Advisory Details (8)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f2a880e802ad12d1e38039d1334fb1475d0f5241
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f1dc8e72de9aabe5d96767a4e97219ac26b79fe5
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a76511bc654819425d3b15e77b523d7f9d81f064
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/484357dff256c816d9466bda35eb765685e4dc86
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3104a3f40feb107f77d7116ad9bf6c210ab7babf
generic

tty: hvc_iucv: fix off-by-one in number of supported devices - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/11207e42a332eb8bbcb9fe74df9edd2a807c5607

Vendor Advisories for CVE-2026-53306(2)

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

Patch Availability(30)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-6.8 (6.8.0-136.136) @ noble2026-08-24ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1075 (5.15.0-1075.79) @ jammy2026-08-24ubuntu
ubuntulinux-tools-nvidia-tegra-rt-5.15 (5.15.0.1064.66~20.04.1) @ focal2026-08-24ubuntu
ubuntulinux-tools-oracle-7.0 (7.0.0-1008.8) @ resolute2026-08-24ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1058.61) @ noble2026-08-24ubuntu
ubuntulinux-tools-oracle-edge (6.8.0-1058.61~22.04.1) @ jammy2026-08-24ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1059.62.1) @ noble2026-08-24ubuntu
ubuntulinux-tools-aws-fips-6.8 (6.8.0-1061.64+fips1) @ noble2026-08-24ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-136.136~22.04.1) @ jammy2026-08-24ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2050.52) @ noble2026-08-24ubuntu
ubuntulinux-virtual-hwe-26.04-edge (7.0.0-28.28) @ resolute2026-08-24ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1009.9) @ resolute2026-08-24ubuntu
ubuntulinux-virtual-hwe-24.04-edge (7.0.0-28.28~24.04.1) @ noble2026-08-24ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1064.72+fips1) @ noble2026-08-24ubuntu
ubuntulinux-tools-nvidia-lowlatency-5.15 (5.15.0.1107.107) @ jammy2026-08-24ubuntu
ubuntulinux-tools-nvidia-tegra-rt-5.15 (5.15.0.1064.64) @ jammy2026-08-24ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-08-24ubuntu
ubuntulinux-tools-aws-lts-24.04 (6.8.0-1061.64+1) @ noble2026-08-24ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1063.71) @ noble2026-08-24ubuntu
ubuntulinux-tools-azure-fde-lts-24.04 (6.8.0-1062.69) @ noble2026-08-24ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1063.71+fips2) @ noble2026-08-24ubuntu
ubuntulinux-tools-azure-fde-6.8 (6.8.0-1062.69~22.04.1) @ jammy2026-08-24ubuntu
ubuntulinux-tools-oracle-lts-22.04 (5.15.0.1109.105) @ jammy2026-08-24ubuntu
ubuntulinux-tools-azure-fde-lts-22.04 (5.15.0.1117.126) @ jammy2026-08-24ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1015.15) @ resolute2026-08-24ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1033.34) @ noble2026-08-24ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1109.115~20.04.1) @ focal2026-08-24ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1117.102) @ jammy2026-08-24ubuntu
ubuntulinux-tools-intel-iot-realtime-5.15 (5.15.0.1104.108) @ jammy2026-08-24ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1112.122~20.04.1) @ focal2026-08-24ubuntu

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

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (496 versions)——
linux-6.16.1.106-3~deb11u1 ... 6.1.174-1~deb11u1 (20 versions)6.1.176-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)6.1.176-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.94-1~bpo12+1 (27 versions)6.12.94-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (137 versions)7.0.10-1—

Weakness Classification(1)

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

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 20× in last 7d / 103× 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.

Showing the most recent 100 of 163 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 12:46 UTCEG score recompute
  3. 2026-08-24 12:46 UTCVendor advisory
  4. 2026-08-24 12:45 UTCGHSA enrichment
  5. 2026-08-23 08:31 UTCEG score recompute
  6. 2026-08-23 08:31 UTCVendor advisory
  7. 2026-08-23 08:31 UTCGHSA enrichment
  8. 2026-08-23 00:19 UTCEPSS rescore
  9. 2026-08-22 09:21 UTCEG score recompute
  10. 2026-08-22 09:21 UTCVendor advisory
  11. 2026-08-22 09:21 UTCGHSA enrichment
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 05:26 UTCEG score recompute
  14. 2026-08-21 05:26 UTCVendor advisory
  15. 2026-08-21 05:26 UTCGHSA enrichment
  16. 2026-08-20 22:55 UTCEPSS rescore
  17. 2026-08-20 06:34 UTCEG score recompute
  18. 2026-08-20 06:34 UTCVendor advisory
  19. 2026-08-20 06:34 UTCGHSA enrichment
  20. 2026-08-19 17:04 UTCEPSS rescore
  21. 2026-08-18 23:36 UTCEG score recompute
  22. 2026-08-18 23:36 UTCVendor advisory
  23. 2026-08-18 23:36 UTCGHSA enrichment
  24. 2026-08-18 13:48 UTCEPSS rescore
  25. 2026-08-17 13:47 UTCEPSS rescore
Show 75 more
  1. 2026-08-16 20:00 UTCEG score recompute
  2. 2026-08-16 20:00 UTCVendor advisory
  3. 2026-08-16 20:00 UTCGHSA enrichment
  4. 2026-08-16 14:56 UTCEPSS rescore
  5. 2026-08-16 02:14 UTCEPSS rescore
  6. 2026-08-15 19:51 UTCEG score recompute
  7. 2026-08-15 19:51 UTCVendor advisory
  8. 2026-08-15 19:51 UTCGHSA enrichment
  9. 2026-08-15 01:30 UTCEPSS rescore
  10. 2026-08-14 20:59 UTCVendor advisory
  11. 2026-08-14 20:59 UTCGHSA enrichment
  12. 2026-08-13 22:07 UTCEG score recompute
  13. 2026-08-13 22:07 UTCVendor advisory
  14. 2026-08-13 22:07 UTCGHSA enrichment
  15. 2026-08-13 22:00 UTCEPSS rescore
  16. 2026-08-12 23:15 UTCEG score recompute
  17. 2026-08-12 23:15 UTCVendor advisory
  18. 2026-08-12 23:15 UTCGHSA enrichment
  19. 2026-08-12 13:51 UTCEPSS rescore
  20. 2026-08-12 00:24 UTCEG score recompute
  21. 2026-08-12 00:24 UTCVendor advisory
  22. 2026-08-12 00:24 UTCGHSA enrichment
  23. 2026-08-11 01:25 UTCEG score recompute
  24. 2026-08-11 01:25 UTCVendor advisory
  25. 2026-08-11 01:25 UTCGHSA enrichment
  26. 2026-08-11 00:00 UTCEPSS rescore
  27. 2026-08-10 02:33 UTCEG score recompute
  28. 2026-08-10 02:33 UTCVendor advisory
  29. 2026-08-10 02:33 UTCGHSA enrichment
  30. 2026-08-09 13:46 UTCEPSS rescore
  31. 2026-08-09 03:42 UTCVendor advisory
  32. 2026-08-09 03:42 UTCGHSA enrichment
  33. 2026-08-08 04:51 UTCEG score recompute
  34. 2026-08-08 04:51 UTCVendor advisory
  35. 2026-08-08 04:51 UTCGHSA enrichment
  36. 2026-08-07 05:59 UTCEG score recompute
  37. 2026-08-07 05:59 UTCVendor advisory
  38. 2026-08-07 05:59 UTCGHSA enrichment
  39. 2026-08-06 13:47 UTCEPSS rescore
  40. 2026-08-06 07:08 UTCEG score recompute
  41. 2026-08-06 07:08 UTCVendor advisory
  42. 2026-08-06 07:08 UTCGHSA enrichment
  43. 2026-08-05 19:17 UTCEPSS rescore
  44. 2026-08-05 08:16 UTCEG score recompute
  45. 2026-08-05 08:16 UTCVendor advisory
  46. 2026-08-05 08:16 UTCGHSA enrichment
  47. 2026-08-04 10:39 UTCEPSS rescore
  48. 2026-08-04 08:49 UTCEG score recompute
  49. 2026-08-04 08:49 UTCVendor advisory
  50. 2026-08-04 08:49 UTCGHSA enrichment
  51. 2026-08-03 10:36 UTCEPSS rescore
  52. 2026-08-03 08:48 UTCVendor advisory
  53. 2026-08-03 08:48 UTCGHSA enrichment
  54. 2026-08-02 09:56 UTCEG score recompute
  55. 2026-08-02 09:56 UTCVendor advisory
  56. 2026-08-02 09:56 UTCGHSA enrichment
  57. 2026-08-02 02:27 UTCEPSS rescore
  58. 2026-08-01 11:04 UTCEG score recompute
  59. 2026-08-01 11:04 UTCVendor advisory
  60. 2026-08-01 11:04 UTCGHSA enrichment
  61. 2026-08-01 04:16 UTCEPSS rescore
  62. 2026-07-31 12:12 UTCEG score recompute
  63. 2026-07-31 12:12 UTCVendor advisory
  64. 2026-07-31 12:12 UTCGHSA enrichment
  65. 2026-07-30 16:28 UTCEPSS rescore
  66. 2026-07-30 13:20 UTCEG score recompute
  67. 2026-07-30 13:20 UTCVendor advisory
  68. 2026-07-30 13:20 UTCGHSA enrichment
  69. 2026-07-30 01:30 UTCEPSS rescore
  70. 2026-07-29 13:27 UTCEG score recompute
  71. 2026-07-29 13:27 UTCVendor advisory
  72. 2026-07-29 13:26 UTCGHSA enrichment
  73. 2026-07-28 15:37 UTCEPSS rescore
  74. 2026-07-28 14:34 UTCVendor advisory
  75. 2026-07-28 14:34 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-53306?
CVE-2026-53306 is a medium vulnerability published on June 26, 2026. In the Linux kernel, the following vulnerability has been resolved: tty: hvc_iucv: fix off-by-one in number of supported devices MAXHVCIUCVLINES == HVCALLOCTTYADAPTERS == 8. This is the number of entries in: static struct hvciucvprivate *hvciucvtable[MAXHVCIUCV_LINES]; Sometimes hvciucvtable[] is…
When was CVE-2026-53306 disclosed?
CVE-2026-53306 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on July 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53306 actively exploited?
CVE-2026-53306 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 97.7% of all scored CVEs.
What is the CVSS score of CVE-2026-53306?
CVE-2026-53306 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-53306?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53306, 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.

Dependency Blast Radius

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