CVE-2026-54786

MEDIUMNVD 5.05.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.0 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 88% 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
5.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.0Exploit: NoneExposed: 0

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

Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36.0.11; versions 37.0.0 through those before 44.0.3; and versions 45.0.0 and 45.0.1 contain a native implementation of WASIp1 which suffers from a leak in the fd_renumber function where the file descriptor being renumbered to is not properly closed. Wasmtime's implementation erroneously only updated the table of descriptors for WASIp1 and didn't update the underlying table of descriptors used by the host. This behavior means that while fd_renumber works correctly from a guest's perspective it ends up leaking resources in the host that aren't cleaned up until the corresponding Store is destroyed. In a loop, guests can use fd_renumber to cause hosts to exhaust both resources and file descriptors. This bug only affects the native implementation of WASIp1, meaning that only runtimes which load core wasm modules and expose fd_renumber are affected. Runtimes are additionally only affected if they expose the ability to acquire a file descriptor, such as opening a file. For runtimes that deny access to files they are unaffected. This issue has been fixed in versions 24.0.10, 36.0.11, 44.0.3, and 45.0.2.

CVSS v3
5.0
EG Score
5.0(medium)
EPSS
12.1%
KEV
Not listed

Published

July 1, 2026

Last Modified

July 2, 2026

Advisory Details (1)

Auto-updated Jul 7, 2026
Patch available. Sources: github.
github Patch Available

Leak in WASIp1 `fd_renumber` implementation · Advisory · bytecodealliance/wasmtime · GitHub

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-3p27-qvp9-27qf

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 19× in last 7d / 27× 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. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-11 06:49 UTCEG score recompute
  5. 2026-07-10 06:11 UTCEG score recompute
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 05:32 UTCEG score recompute
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-08 15:16 UTCEPSS rescore
  11. 2026-07-08 04:53 UTCEG score recompute
  12. 2026-07-07 13:46 UTCEPSS rescore
  13. 2026-07-07 13:46 UTCEPSS rescore
  14. 2026-07-07 04:08 UTCEG score recompute
  15. 2026-07-06 16:27 UTCEPSS rescore
  16. 2026-07-06 16:27 UTCEPSS rescore
  17. 2026-07-06 03:28 UTCEG score recompute
  18. 2026-07-06 02:23 UTCEPSS rescore
  19. 2026-07-06 02:23 UTCEPSS rescore
  20. 2026-07-05 02:48 UTCEG score recompute▲ 2.70
  21. 2026-07-05 02:31 UTCEPSS rescore
  22. 2026-07-05 02:30 UTCEPSS rescore
  23. 2026-07-04 06:31 UTCEPSS rescore
  24. 2026-07-04 06:31 UTCEPSS rescore
  25. 2026-07-02 20:05 UTCNVD updateCVSS v3 → 5 · severity → MEDIUM
Show 2 more
  1. 2026-07-01 23:09 UTCEG score recompute
  2. 2026-07-01 23:08 UTCNVD updatefirst tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-54786?
CVE-2026-54786 is a medium vulnerability published on July 1, 2026. Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36.0.11; versions 37.0.0 through those before 44.0.3; and versions 45.0.0 and 45.0.1 contain a native implementation of WASIp1 which suffers from a leak in the fdrenumber function where the…
When was CVE-2026-54786 disclosed?
CVE-2026-54786 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54786 actively exploited?
CVE-2026-54786 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 12.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54786?
CVE-2026-54786 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2026-54786?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54786, 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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