RUSTSEC-2026-0501

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Source

https://rustsec.org/advisories/RUSTSEC-2026-0501

Import Source

https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0501.json

JSON Data

https://api.osv.dev/v1/vulns/RUSTSEC-2026-0501

Aliases

GHSA-cwxv-4866-5gq2

Published

2026-11-12T12:00:00Z

Modified

2026-11-12T08:00:03Z

Severity

9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator

Summary

Shamir backup recovery accepts a share at x = 0, so a supplied share can substitute the recovered private key

Details

KeyShares::from_backup_format (the Shamir backup share reader, public since 0.2.0, the crate's first release) accepted a share whose x coordinate is 0, and KeyShares::recover_private_key interpolates the shares at x = 0 to recover the key. At an x of 0 the interpolation answers that share's y value alone, so an attacker who supplies one share in that form — with the share's integrity tag ground to match the honest set's — chooses the recovered key outright. The non-canonical zero x = p works the same way, and a repeated x past the threshold window also passed.

An application that recovers a Shamir backup from shares it did not produce — a custodian's medium, a share pasted by hand, a set restored from another writer — could be handed the attacker's key as the recovered one. A set the crate's own writer produces never carries such a share; the door is the reader.

0.8.7 refuses such a set before interpolating (the 0.9 line's next prerelease carries the same refusal). Where upgrading is not possible, before recovering split each share on . into four fields, base58-decode the x field, and refuse the set if it decodes to zero (the one-character field 1, or a value at or above the field prime) or if two shares carry the same x.

Database specific

{
    "license": "CC0-1.0"
}

References

Affected packages

crates.io / bsv-rs

Package

Name: bsv-rs; View open source insights on deps.dev
Purl: pkg:cargo/bsv-rs

Affected ranges

Type: SEMVER
Events: Introduced

0.0.0-0

Fixed

0.8.7

Introduced

0.9.0-beta.1

Fixed

0.9.0-beta.7.0

Ecosystem specific

{
    "affected_functions": null,
    "affects": {
        "arch": [],
        "functions": [
            "bsv_rs::primitives::bsv::shamir::KeyShares::from_backup_format",
            "bsv_rs::primitives::bsv::shamir::KeyShares::recover_private_key"
        ],
        "os": []
    }
}