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bsv-rs signature check bypass in KVStoreInterpreter

RUSTSEC-2026-0529GHSA-MJ2M-JXGV-R446

Exploited
No known exploitation
Fix
Fixed in 0.8.9, 0.9.0-beta.7.0
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 0.8.9, 0.9.0-beta.7.0.

Published
Last modified
Reference
Last checked
10/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

The `KVStoreInterpreter::verify_signature_legacy` function in bsv-rs always returns `true` and never checks the token's signature or key. An application that uses it to check a KVStore token it did not write, such as an overlay lookup result or a transaction output from a peer, and then acts on that result can accept a value no controller signed, attributed to the controller the token names.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

KVStoreInterpreter::verify_signature_legacy(&PushDrop, &PublicKey), public and deprecated since 0.2.0 (the crate's first release), read neither argument and answered true. A KVStore token signed by nobody, a signed token checked against a key other than its controller's, and a PushDrop with no fields each passed. Its documentation said it delegated to the KVStoreFields-based verifier; it did not.

An application that checks, with this function, a KVStore token it did not write (an overlay lookup's answer, or a transaction output a peer hands it) and acts on true accepts a value no controller signed, attributed to whatever controller the token names. No caller in the crate itself uses the function. This was run on 0.2.0, 0.5.0, 0.8.0, 0.8.7, 0.8.8, 0.9.0-beta.1 and 0.9.0-beta.7 as crates.io serves them, and the source of all 63 published versions carries the same constant body (the yanked 0.3.21 included).

0.8.9 answers true only for a token whose controller field is the given key and whose last field is that key's signature over the others (the 0.9 line's next prerelease carries the same fix). There is no workaround: upgrade to 0.8.9, or, on the 0.9 line, to its next prerelease.

cve.now Index

10Pcve.now Index 10 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach10/20Affects crates.io packages
  • Severity?/10Unknown. No CVSS score or vendor rating
  • No patch0/5No signal

What would change the score

  • Would score about 65 if added to CISA KEV
  • Would score about 60 if CISA's SSVC rates exploitation active
  • Would score about 32 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

  • Upgrade to a fixed version: 0.8.9, 0.9.0-beta.7.0.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by RUSTSEC-2026-0529 (KVStoreInterpreter::verify_signature_legacy answers true for every token and every key), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for RUSTSEC-2026-0529 (entry last updated 2026-11-13):
Affected:
- crates.io package bsv-rs: from 0.0.0-0, fixed in 0.8.9; from 0.9.0-beta.1, fixed in 0.9.0-beta.7.0
Fixed versions: 0.8.9, 0.9.0-beta.7.0.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: RUSTSEC-2026-0529 is not listed as of cve.now's last read.
This KEV status is for RUSTSEC-2026-0529 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (crates.io): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://rustsec.org/advisories/RUSTSEC-2026-0529.html
- https://crates.io/crates/bsv-rs
- https://github.com/Calhooon/bsv-rs/blob/v0.8.9/CHANGELOG.md
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/RUSTSEC-2026-0529
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "RUSTSEC-2026-0529"}.

Timeline

  1. Advisory published
  2. Record last updated
  3. First seen by cve.now

Affected versions

  • bsv-rscrates.io

    From 0.0.0-0 · fixed in 0.8.9; From 0.9.0-beta.1 · fixed in 0.9.0-beta.7.0

Evidence 3

Other links · 3

  1. Advisory
  2. Repository
  3. Link

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about RUSTSEC-2026-0529

Is RUSTSEC-2026-0529 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by RUSTSEC-2026-0529?

bsv-rs (crates.io): from 0.0.0-0 before 0.8.9; from 0.9.0-beta.1 before 0.9.0-beta.7.0.Source: cve.now feed data

How do I fix RUSTSEC-2026-0529?

Upgrade to a fixed version: 0.8.9, 0.9.0-beta.7.0.Source: cve.now feed data

Sources

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