WEP fails with Unsupported authentication algorithm (7820)

[Yegor Yefremov]

During the transition from wpa_supplicant v2.4 to v2.9 on a legacy
project I get the following message:

mgmt::auth
authentication: STA=7c:dd:90:44:a5:83 auth_alg=7820
auth_transaction=112 status_code=31962 wep=1 seq_ctrl=0x60a0
Unsupported authentication algorithm (7820)
authentication reply: STA=7c:dd:90:44:a5:83 auth_alg=7820
auth_transaction=113 resp=13 (IE len=0) (dbg=handle-auth)

My conf file looks like this:

ctrl_interface=/var/run/wpa_supplicant
ap_scan=1

network={
        ssid="myssid"
        mode=2
        frequency=2447
        key_mgmt=NONE
        wep_key0="passw"
        wep_tx_keyidx=0
}

This configuration was working in v2.4. I tried v2.6, v2.8, v2.9 and
master. The same error.

Any idea?

Regards,
Yegor