CVE-2026-54786
published 2026-07-01CVE-2026-54786: 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…
PriorityP428medium5CVSS 3.1
AVNACLPRLUINSCCNINAL
EPSS
0.22%
12.1th percentile
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.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| bytecodealliance | wasmtime | < 24.0.10 | 24.0.10 |
| bytecodealliance | wasmtime | — | — |
| bytecodealliance | wasmtime | — | — |
| bytecodealliance | wasmtime | — | — |
| bytecodealliance | wasmtime | >= 25.0.0 < 36.0.11 | 36.0.11 |
| bytecodealliance | wasmtime | >= 37.0.0 < 44.0.3 | 44.0.3 |
| bytecodealliance | wasmtime | >= 45.0.0 < 45.0.2 | 45.0.2 |
| rhcl-1 | wasm-shim-rhel9 | — | — |
| rust-lang | rust | — | — |
CVSS provenance
nvdv3.15.0MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L
nvdv4.02.3LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat5.0MEDIUM
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GHSA
Wasmtime has a leak in WASIp1 `fd_renumber` implementation
ghsa·2026-08-26
CVE-2026-54786 [LOW] CWE-400 Wasmtime has a leak in WASIp1 `fd_renumber` implementation
Wasmtime has a leak in WASIp1 `fd_renumber` implementation
### Impact
Wasmtime's native implementation of WASIp1 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. This means that guests can, in a loop, use `fd_renumber` to cause hosts to exhaust resources or exhaust file descriptors.
This bug only affects the native implementation of WASIp1. This means that only runti
VulDB
bytecodealliance wasmtime up to 24.0.9/36.0.10/44.0.2/45.0.1 File Descriptor fd_renumber release of resource (GHSA-3p27-qvp9-27qf)
vuldb·2026-07-02·CVSS 2.3
CVE-2026-54786 [LOW] bytecodealliance wasmtime up to 24.0.9/36.0.10/44.0.2/45.0.1 File Descriptor fd_renumber release of resource (GHSA-3p27-qvp9-27qf)
A vulnerability marked as problematic has been reported in bytecodealliance wasmtime up to 24.0.9/36.0.10/44.0.2/45.0.1. This issue affects the function fd_renumber of the component File Descriptor Handler. Performing a manipulation results in missing release of resource.
This vulnerability is reported as CVE-2026-54786. The attack is possible to be carried out remotely. No exploit exists.
It is suggested to upgrade the affected component.
Red Hat
Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
vendor_redhat·2026-07-01·CVSS 5.0
CVE-2026-54786 [MEDIUM] CWE-772 Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
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 us
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-54786 tree-sitter0.25: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
bugzilla·2026-07-03·CVSS 5.0
CVE-2026-54786 [MEDIUM] CVE-2026-54786 tree-sitter0.25: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
CVE-2026-54786 tree-sitter0.25: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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 underlyi
Bugzilla
CVE-2026-54786 tree-sitter: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
bugzilla·2026-07-03·CVSS 5.0
CVE-2026-54786 [MEDIUM] CVE-2026-54786 tree-sitter: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
CVE-2026-54786 tree-sitter: Wasmtime: Leak in WASIp1 `fd_renumber` implementation [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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 t
Bugzilla
CVE-2026-54786 Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
bugzilla·2026-07-01·CVSS 5.0
CVE-2026-54786 [MEDIUM] CVE-2026-54786 Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
CVE-2026-54786 Wasmtime: Wasmtime: Leak in WASIp1 `fd_renumber` implementation
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
2026-07-01
Published