Buffer overflow in Yosyshq Yosys
CVE-2026-3407
A vulnerability was determined in YosysHQ yosys up to 0.62. This affects the function Yosys::RTLIL::Const::set of the file kernel/rtlil.h of the component BLIF File Parser. This manipulation causes heap-based buffer overflow. It is possible to launch the attack on the local host. The exploit has been publicly disclosed and may be utilized. Applying a patch is the recommended action to fix this issue. It appears that the issue is not reproducible all the time.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (6.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 6.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Yosyshq Yosys — versions 0.1, 0.2, 0.3
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, vdb-entry)
- vuldb.com/ (signature, permissions-required)
- vuldb.com/ (third-party-advisory)
- github.com/YosysHQ/yosys/issues/5677 (issue-tracking)
- github.com/YosysHQ/yosys/pull/5680 (issue-tracking, patch)
- github.com/oneafter/0210/blob/main/yo2/repro (exploit)
- github.com/YosysHQ/yosys/pull/5681 (issue-tracking, patch)
- github.com/YosysHQ/yosys/ (product)
Frequently asked questions
- What is CVE-2026-3407?
- CVE-2026-3407 is a low-severity vulnerability in Yosyshq Yosys, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 3.3/10. Published 2026-03-02.
- How severe is CVE-2026-3407?
- Low severity. CVSS v3 base score is 3.3 out of 10.