CVE-2026-107840 yopass Prometheus metrics middleware allows remote memory exhaustion through unbounded method labels

What is CVE-2026-107840?

CVE-2026-107840 is a high-severity denial of service vulnerability in jhaals yopass, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

yopass is a service for securely sharing secrets, passwords, and files. Prior to version 14.7.0, the Prometheus metrics middleware in pkg/server/server.go uses the attacker-controlled r.Method value directly as the method label for yopass_http_requests_total and yopass_http_request_duration_seconds. Because the catch-all route accepts arbitrary HTTP method tokens, an unauthenticated remote attacker can submit many unique methods and create metric series that the Prometheus registry never evicts. The resulting monotonic memory growth can OOM-kill the process, while the expanding registry also degrades /metrics scrape latency and can blind monitoring. This issue is fixed in version 14.7.0.

Weakness: CWE-400

Which versions are affected by CVE-2026-107840?

3 open source packages ship an affected version, including github.com/jhaals/yopass.

How do I fix CVE-2026-107840?

Upgrade github.com/jhaals/yopass to 0.0.0-20260727191436-61e31ead04a4 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-107840 being exploited?

There is no known exploitation of CVE-2026-107840 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6r69-c6wg-7g8m, GO-2026-6720.