NVD / CVE Program· CNA GitHub_M

CVE-2026-54786: Wasmtime: Leak in WASIp1 `fd_renumber` implementation

Noroxi assessment

Priority: Monitor (action score 9/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.36% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: wasmtime-wasi (crates.io) 24.0.10, 36.0.11, 44.0.3; rust-wasmtime (Debian:14) 36.0.11+dfsg-1.

Low priority for now. Upgrade to wasmtime-wasi (crates.io) 24.0.10, 36.0.11, 44.0.3; rust-wasmtime (Debian:14) 36.0.11+dfsg-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 2.3 · v4.0—No exploit Fix available

Denial of service

Published: Jul 1, 2026
Updated: Oct 25, 2026
EPSS: 0.3% · 30th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 9 / 40 · 2.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 2.3; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
bytecodealliance	wasmtime	cpe:2.3:a:bytecodealliance:wasmtime

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

bytecodealliance wasmtimebefore 24.0.10
bytecodealliance wasmtime25.0.0 and later · before 36.0.11
bytecodealliance wasmtime37.0.0 and later · before 44.0.3
bytecodealliance wasmtime45.0.0 and later · before 45.0.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

bytecodealliance wasmtime
- < 24.0.10, >= 25.0.0, < 36.0.11, >= 37.0.0, < 44.0.3, >= 45.0.0, < 45.0.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
crates.io	wasmtime-wasi	from 0.0.0-0 · before 24.0.10	24.0.10
crates.io	wasmtime-wasi	from 25.0.0 · before 36.0.11	36.0.11
crates.io	wasmtime-wasi	from 37.0.0 · before 44.0.3	44.0.3
crates.io	wasmtime-wasi	from 45.0.0 · before 45.0.2	45.0.2
crates.io	wasmtime-wasi	before 24.0.10	24.0.10
Debian:13	rust-wasmtime	from 0	—
Debian:14	rust-wasmtime	before 36.0.11+dfsg-1	36.0.11+dfsg-1

Same product

bytecodealliance: all records

Other highest-scoring records for the same primary product.

CVE-2026-115893Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
39Monitor
CVE-2026-115889Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation
39Monitor
CVE-2022-39394wasmtime_trap_code C API function has out of bounds write vulnerability
39Monitor

Published before and after this one in the same product

← EarlierCVE-2026-44216May 14, 2026 · Wasmtime: Panic when allocating a table exceeding the size of the host's address space
23Monitor
← EarlierCVE-2026-47261Jun 15, 2026 · Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` host restriction
30Monitor
Later →CVE-2026-58494Jul 8, 2026 · Wasmtime: WASI hard links bypass wasmtime-wasi's FilePerms for destination
26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
crates.io:wasmtime-wasi	24.0.10	Package registry (OSV)
crates.io:wasmtime-wasi	36.0.11	Package registry (OSV)
crates.io:wasmtime-wasi	44.0.3	Package registry (OSV)
crates.io:wasmtime-wasi	45.0.2	Package registry (OSV)
debian:rust-wasmtime	36.0.11+dfsg-1 · Debian:14	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-115388113 days apartWasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Memory Exhaustion DoS via wasmtime-wasi-http Outgoing Body Write
27Monitor
CVE-2026-115390113 days apartWasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 Fuel Accounting Bypass DoS
27Monitor
CVE-2026-27204127 days apartWasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion
27Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: X

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS: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

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

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

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records