# CVE-2025-29779: Post-Quantum Secure Feldman's Verifiable Secret Sharing has Inadequate Fault Injection Countermeasures in `secure_redundant_execution`

> Inadequate fault injection countermeasures allow attackers with physical access to bypass security checks, extract secret coefficients, or accept invalid shares in the VSS scheme.

- **Severity:** Medium 5.4 (`CVSS:4.0/AV:P/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Mar 2025
- **Updated:** 19 Mar 2025
- **Also known as:** GHSA-r8gc-qc2c-c7vh

## What is CVE-2025-29779?

CVE-2025-29779 is a medium-severity vulnerability in DavidOsipov PostQuantum-Feldman-VSS, published on 14 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Post-Quantum Secure Feldman's Verifiable Secret Sharing provides a Python implementation of Feldman's Verifiable Secret Sharing (VSS) scheme. In versions 0.8.0b2 and prior, the `secure_redundant_execution` function in feldman_vss.py attempts to mitigate fault injection attacks by executing a function multiple times and comparing results. However, several critical weaknesses exist. Python's execution environment cannot guarantee true isolation between redundant executions, the constant-time comparison implementation in Python is subject to timing variations, the randomized execution order and timing provide insufficient protection against sophisticated fault attacks, and the error handling may leak timing information about partial execution results. These limitations make the protection ineffective against targeted fault injection attacks, especially from attackers with physical access to the hardware. A successful fault injection attack could allow an attacker to bypass the redundancy check mechanisms, extract secret polynomial coefficients during share generation or verification, force the acceptance of invalid shares during verification, and/or manipulate the commitment verification process to accept fraudulent commitments. This undermines the core security guarantees of the Verifiable Secret Sharing scheme. As of time of publication, no patched versions of Post-Quantum Secure Feldman's Verifiable Secret Sharing exist, but other mitigations are available. Long-term remediation requires reimplementing the security-critical functions in a lower-level language like Rust. Short-term mitigations include deploying the software in environments with physical security controls, increasing the redundancy count (from 5 to a higher number) by modifying the source code, adding external verification of cryptographic operations when possible, considering using hardware security modules (HSMs) for key operations.

Weakness: CWE-1279 (Cryptographic Operations are Run Before Supporting Units are Ready), CWE-1240 (Use of a Cryptographic Primitive with a Risky Implementation)

## Which versions are affected by CVE-2025-29779?

2 open source packages ship an affected version, including PostQuantum-Feldman-VSS and postquantum-feldman-vss.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `PostQuantum-Feldman-VSS` | PyPI | All versions to 0.8.0b2 | None |
| `postquantum-feldman-vss` | PyPI | All versions to 0.8.0b2 | None |

## How do I fix CVE-2025-29779?

No fix has been published for CVE-2025-29779 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-29779 being exploited?

There is no known exploitation of CVE-2025-29779 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-29779 and fix it if it is affected.

What it is: CVE-2025-29779 is a medium-severity vulnerability in DavidOsipov PostQuantum-Feldman-VSS, published on 14 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-29779 in the wild and no public exploit code.

Affected packages and fixed versions:
- PostQuantum-Feldman-VSS (PyPI): affected all versions up to 0.8.0b2; no fix listed
- postquantum-feldman-vss (PyPI): affected all versions up to 0.8.0b2; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-29779/ (Markdown: https://insights.sbomify.com/CVE-2025-29779/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-29779
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-29779
- OSV: https://osv.dev/vulnerability/CVE-2025-29779

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-29779/
Summaries are generated and may contain mistakes; the official description above is the record.