CVE-2026-71271: Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass

Severity: high (CVSS 8.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-10-24
Weakness: CWE-918

Description

Memos' webhook URL validation, isReservedIP (internal/webhook/validate.go), checks a candidate IP against a reservedCIDRs list that omits 0.0.0.0/8 and never calls ip.IsUnspecified — unlike the correctly implemented sibling function isInternalIP in internal/httpgetter/html_meta.go, which does.

Affected products

usememos/memos: through 0.29.1

References

https://github.com/usememos/memos
https://github.com/usememos/memos/blob/main/internal/webhook/validate.go

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