CVE-2026-27137: Incorrect enforcement of email constraints in crypto/x509
CSIRTS triage
- What
- Crypto/x509 package does not properly enforce email constraints in certificates.
- Who is affected
- Go applications using x509 certificate validation with email constraints.
- Urgency
- Medium priority; not currently exploited but weakens email-based identity verification.
- Action
- Update to patched Go version when available.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27137
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-271370.61% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 47% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-27137 | coverage & exploitation status | NVD · CVE.org |
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