CVE-2025-53901
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Wasmtime has host panic with `fd_renumber` WASIp1 function
rank 14 = 0 + 9 + 0 + 5 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00334 · without this subject the record ranks 14
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 3.5, from the CNA · without this subject the record ranks 5
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 14
How much of the world it touches
NVD CPE configurations
3 products in the CPE ranges · without this subject the record ranks 9
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 14
$4,010 = $4.99M incident cost x 0.24048551839932833 exposure x 0.00334 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
Running bytecodealliance wasmtime? Check your version
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.4, 33.0.2, and 34.0.2, a bug in Wasmtime's implementation of the WASIp1 set of import functions can lead to a WebAssembly guest inducing a panic in the host (embedder). The specific bug is triggered by calling `path_open` after calling `fd_renumber` with either two equal argument values or a second argument being equal to a previously-closed file descriptor number value. The corrupt state introduced in `fd_renumber` will lead to the subsequent opening of a file descriptor to panic. This panic cannot introduce memory unsafety or allow WebAssembly to break outside of its sandbox, however. receipt
Read the rest of the CNA's description
There is no possible heap corruption or memory unsafety from this panic. This bug is in the implementation of Wasmtime's `wasmtime-wasi` crate which provides an implementation of WASIp1. The bug requires a specially crafted call to `fd_renumber` in addition to the ability to open a subsequent file descriptor. Opening a second file descriptor is only possible when a preopened directory was provided to the guest, and this is common amongst embeddings. A panic in the host is considered a denial-of-service vector for WebAssembly embedders and is thus a security issue in Wasmtime. This bug does not affect WASIp2 and embedders using components. In accordance with Wasmtime's release process, patch releases are available as 24.0.4, 33.0.2, and 34.0.2. Users of other release of Wasmtime are recommended to move to a supported release of Wasmtime. Embedders who are using components or are not providing guest access to create more file descriptors (e.g. via a preopened filesystem directory) are not affected by this issue. Otherwise, there is no workaround at this time, and affected embeddings are recommended to update to a patched version which will not cause a panic in the host.
NVD's analysis a second authority
- weakness
- CWE-672
- affected versions
- bytecodealliance wasmtime < 24.0.4; bytecodealliance wasmtime >= 33.0.0 < 33.0.2; bytecodealliance wasmtime >= 34.0.0 < 34.0.2
- also scored by
- [email protected] 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
check it yourself github.com docs.wasmtime.dev docs.wasmtime.dev github.com github.com receipt
Movement the material steps
Show all 20 observations
20 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 1 year, 1 month when this index was last written.
Siblings and hubs
Records related to this one
None. No alias set, and nothing in the corpus cites this identifier or shares its product family within 60 days.
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What usually comes next
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