CVE-2026-32853

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, 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: 0%CVSS: 8.1Exploit: Elevated riskExposed: 0

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

LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.

CVSS v3
8.1
EG Score
8.1(medium)
EG Risk
67(Attend)
EG Risk 67/100SSVC: Attend

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%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

March 24, 2026

Last Modified

July 14, 2026

Advisory Details (3)

Auto-updated Jul 14, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github Patch Available🟡 PoC Available

Heap Out-of-Bounds Read in HandleUltraZipBPP due to unchecked subrectangle count · Advisory · LibVNC/libvncserver · GitHub

https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj
generic

LibVNCServer UltraZip Encoding Heap Out-of-bounds Read | Advisories | VulnCheck

https://www.vulncheck.com/advisories/libvncserver-ultrazip-encoding-heap-out-of-bounds-read
github_commit

commit 009008e2f4d5 (LibVNC/libvncserver)

Fix landed in LibVNC/libvncserver commit 009008e2f4d5 — awaiting tagged release

https://github.com/LibVNC/libvncserver/commit/009008e2f4d5a54dd71f422070df3af7b3dbc931

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 32× 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. 2026-08-01 04:16 UTCEPSS rescore
  2. 2026-07-30 16:28 UTCEPSS rescore
  3. 2026-07-30 01:30 UTCEPSS rescore
  4. 2026-07-27 14:13 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-25 14:18 UTCEPSS rescore
  8. 2026-07-25 14:18 UTCEPSS rescore
  9. 2026-07-24 14:17 UTCEPSS rescore
  10. 2026-07-24 14:17 UTCEPSS rescore
  11. 2026-07-23 14:18 UTCEPSS rescore
  12. 2026-07-23 14:18 UTCEPSS rescore
  13. 2026-07-23 03:09 UTCEG score recompute▲ 1.20
  14. 2026-07-22 14:08 UTCEPSS rescore
  15. 2026-07-21 15:24 UTCEPSS rescore
  16. 2026-07-21 15:24 UTCEPSS rescore
  17. 2026-07-20 17:08 UTCEPSS rescore
  18. 2026-07-20 17:08 UTCEPSS rescore
  19. 2026-07-19 14:31 UTCEPSS rescore
  20. 2026-07-19 14:31 UTCEPSS rescore
  21. 2026-07-19 02:29 UTCEPSS rescore
  22. 2026-07-18 10:04 UTCEPSS rescore
  23. 2026-07-18 10:04 UTCEPSS rescore
  24. 2026-07-16 17:03 UTCEPSS rescore
  25. 2026-07-16 17:03 UTCEPSS rescore
Show 7 more
  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-15 02:00 UTCEPSS rescore
  5. 2026-07-14 19:21 UTCNVD updateCVSS v3 → 8.1 · severity → HIGH
  6. 2026-07-14 19:01 UTCEG score recompute
  7. 2026-07-14 19:00 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-32853?
CVE-2026-32853 is a high vulnerability published on March 24, 2026. LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the…
When was CVE-2026-32853 disclosed?
CVE-2026-32853 was first published in the National Vulnerability Database on March 24, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-32853 actively exploited?
CVE-2026-32853 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 64.0% of all scored CVEs.
What is the CVSS score of CVE-2026-32853?
CVE-2026-32853 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-32853?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-32853, 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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