CVE-2018-6307

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 27%CVSS: 8.1Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

CVSS v3
8.1
EG Score
8.1HIGHmedium confidence
EG Risk
57
EG Risk 57/100CISA SSVC

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
Severity81% × 45%
Exploitation40% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
27%
EPSS %ILE
97th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: elevated) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

December 19, 2018

Last Modified

November 21, 2024

Advisory Details (5)

Auto-updated Sep 11, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 1979-1] italc security update

https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
generic Patch Available

[SECURITY] [DLA 1617-1] libvncserver security update

https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
generic

KLCERT-18-026: LibVNC Heap Use-After-Free | Kaspersky ICS CERT EN

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/
generic

SECURITY: Heap use-after-free in tightvnc-filetransfer extension · Issue #241 · LibVNC/libvncserver · GitHub

https://github.com/LibVNC/libvncserver/issues/241
generic

[SECURITY] [DSA 4383-1] libvncserver security update

https://www.debian.org/security/2019/dsa-4383

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibvncserver1 (0.9.10+dfsg-3ubuntu0.16.04.3) @ xenial2026-05-28ubuntu

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

(7 across 6 ecosystems)
Debian:8(2)
PackageVulnerable rangeFix by version rangeDependents
italc1:2.0.2+dfsg1-2
  • every version up to 1:2.0.2+dfsg1-2+deb8u1: fixed in 1:2.0.2+dfsg1-2+deb8u1
—
libvncserver0.9.9+dfsg-6.1, 0.9.9+dfsg2-6.1+deb8u1, 0.9.9+dfsg2-6.1+deb8u2, 0.9.9+dfsg2-6.1+deb8u3
  • every version up to 0.9.9+dfsg2-6.1+deb8u4: fixed in 0.9.9+dfsg2-6.1+deb8u4
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libvncserver—
  • every version up to 0.9.11+dfsg-1.2: fixed in 0.9.11+dfsg-1.2
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libvncserver—
  • every version up to 0.9.11+dfsg-1.2: fixed in 0.9.11+dfsg-1.2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libvncserver—
  • every version up to 0.9.11+dfsg-1.2: fixed in 0.9.11+dfsg-1.2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libvncserver—
  • every version up to 0.9.11+dfsg-1.2: fixed in 0.9.11+dfsg-1.2
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
libvncserver0.9.11+dfsg-1, 0.9.11+dfsg-1+deb9u1, 0.9.11+dfsg-1.1, 0.9.11+dfsg-1.2
  • every version up to 0.9.11+dfsg-1.3~deb9u1: fixed in 0.9.11+dfsg-1.3~deb9u1
—

Weakness Classification(1)

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

All Vendor Advisories

(1)

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 6× in last 7d / 21× 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 144 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2018-6307?
CVE-2018-6307 is a high vulnerability published on December 19, 2018. LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.
When was CVE-2018-6307 disclosed?
CVE-2018-6307 was first published on December 19, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-6307 actively exploited?
CVE-2018-6307 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27% probability of exploitation in the next 30 days (97th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2018-6307?
CVE-2018-6307 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2018-6307?
A fix for CVE-2018-6307 is available: update to the fixed version the vendor names in its advisory.

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