CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NCVE-2026-56864
High (7.5). EPSS 0.3% chance of exploitation in the next 30 days. Fixed in toolchain 1.25.13, 1.26.6, 1.27.0-rc.3.
A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy
Severity
- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 22% of CVEs (scores of 2026-10-31)
- CWE
- CWE-347
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GO-2026-6180 | Go | toolchain | <1.25.13 >=1.26.0-0 <1.26.6 >=1.27.0-0 <1.27.0-rc.3 | 1.25.13, 1.26.6, 1.27.0-rc.3 |
| GO-2026-6180 | Go | golang.org/x/mod | <0.40.0 | 0.40.0 |