Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Go standard library (net package) versions before 1.25.10 and from 1.26.0 up to but not including 1.26.3 are affected. When LookupCNAME uses the cgo DNS resolver, a very long CNAME response can cause a double-free of C memory and crash the program. The source does not say what an attacker must control to trigger this. Upgrade to Go 1.25.10 or 1.26.3.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | ADP (CISA-ADP) |
- CISA KEV Not listed.
- EPSS 0.0088, the 59th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:12 UTC First seen by agentprime
- 31 Oct 2026, 14:12 UTC Confirmed by OSV