CVE-2025-24898

Description

In `openssl` versions before `0.10.70`, `ssl::select_next_proto` can return a slice pointing into the `server` argument's buffer but with a lifetime bound to the `client` argument. In situations where the `server` buffer's lifetime is shorter than the `client` buffer's, this can cause a use after free. This could cause the server to crash or to return arbitrary memory contents to the client. `openssl` 0.10.70 fixes the signature of `ssl::select_next_proto` to properly constrain the output buffer's lifetime to that of both input buffers. In standard usage of `ssl::select_next_proto` in the callback passed to `SslContextBuilder::set_alpn_select_callback`, code is only affected if the `server` buffer is constructed *within* the callback. For example: Not vulnerable - the server buffer has a `'static` lifetime: ```rust builder.set_alpn_select_callback(|_, client_protos| { ssl::select_next_proto(b"\x02h2", client_protos).ok_or_else(AlpnError::NOACK) }); ``` Not vulnerable - the server buffer outlives the handshake: ```rust let server_protos = b"\x02h2".to_vec(); builder.set_alpn_select_callback(|_, client_protos| { ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK) }); ``` Vulnerable - the server buffer is freed when the callback returns: ```rust builder.set_alpn_select_callback(|_, client_protos| { let server_protos = b"\x02h2".to_vec(); ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK) }); ```

How to fix CVE-2025-24898

To remediate CVE-2025-24898, upgrade the affected package to a fixed version below.

—upgrade to 0.10.70 or later
—upgrade to 0.10.70 or later
—upgrade to 0.10.29-1+deb11u1 or later
—upgrade to 0.10.29-1+deb11u1 or later

Is CVE-2025-24898 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (4)

>= 0.10.0, < 0.10.70
>= 0.0.0-0, < 0.10.70
from 0, < 0.10.29-1+deb11u1
from 0, < 0.10.29-1+deb11u1

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 4.0	—	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N