usememos Memos up to 0.29.1 Webhook Dispatch webhook.go safeDialContext dns rebinding

Summaryinfo

A vulnerability classified as critical was found in usememos Memos up to 0.29.1. Impacted is the function safeDialContext of the file internal/webhook/webhook.go of the component Webhook Dispatch. Such manipulation leads to dns rebinding. This vulnerability is traded as CVE-2026-71272. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in usememos Memos up to 0.29.1 and classified as critical. Affected by this issue is the function safeDialContext of the file internal/webhook/webhook.go of the component Webhook Dispatch. The manipulation with an unknown input leads to a dns rebinding vulnerability. Using CWE to declare the problem leads to CWE-350. The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Memos' webhook dispatch function safeDialContext() (internal/webhook/webhook.go) resolves the target hostname via net.DefaultResolver.LookupHost() and validates the resulting IPs against reserved ranges, but then dials net.JoinHostPort(host, port) using the original hostname rather than the already-validated IP address. Because net.Dialer.DialContext() performs its own independent DNS resolution, an attacker controlling DNS for the webhook's hostname (e.g. via a short TTL) can return a public, allowed IP during validation and a different, internal IP at dial time — a classic time-of-check/time-of-use DNS-rebinding bypass of the SSRF protection.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-71272 since 08/05/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/05/2026). The MITRE ATT&CK project declares the attack technique as T1583.002.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• usememos

Name

• Memos

Version

• 0.29.0
• 0.29.1

License

• open-source

CPE 2.3info

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CPE 2.2info

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