# CVE-2026-109425: Tink-go 2.8.0 Keyset Validation Bypass via NewHandleWithNoSecrets

> Attackers can bypass keyset validation in Tink-go by supplying malformed keysets, leading to inconsistent security states in applications relying on handle construction.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-109425, GHSA-5fgm-q74f-6j8f, UBUNTU-CVE-2026-109425

## What is CVE-2026-109425?

CVE-2026-109425 is a medium-severity missing authorization vulnerability in tink-crypto tink-go, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Tink-go (tink-crypto/tink-go) through 2.8.0 contains an input-validation vulnerability where keyset.NewHandleWithNoSecrets() and ReadWithNoSecrets() skip the structural Validate() step before constructing a keyset.Handle, allowing malformed public or no-secret keysets that violate Tink's keyset invariants to be accepted. Attackers can supply a malformed keyset, such as one with an enabled public key lacking a valid primary key or a DESTROYED key with no KeyData, causing inconsistent downstream validation where functions like jwt.JWKSetFromPublicKeysetHandle() process the invalid handle and produce a JWK set, potentially misleading applications that rely on successful handle construction as proof of keyset integrity.

Weakness: CWE-1286 (Improper Validation of Syntactic Correctness of Input)

## Which versions are affected by CVE-2026-109425?


## How do I fix CVE-2026-109425?

No fix has been published for CVE-2026-109425 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-109425 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109425 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109425 and fix it if it is affected.

What it is: CVE-2026-109425 is a medium-severity missing authorization vulnerability in tink-crypto tink-go, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109425 exists.

Affected product: tink-crypto tink-go. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-109425/ (Markdown: https://insights.sbomify.com/CVE-2026-109425/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109425
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109425
- OSV: https://osv.dev/vulnerability/CVE-2026-109425

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-109425/
Summaries are generated and may contain mistakes; the official description above is the record.