Compatibility Report

• Name of the game with compatibility issues: Aniimo
• Steam AppID of the game: 4126040

System Information

• GPU: Radeon RX 9070 XT (RADV)
• Kernel version: 7.2.4-3-cachyos / 7.2.5-cachyos (reproduced across kernel updates)
• Proton versions tested: Proton 10.0-4b, Proton Experimental (official, build experimental-bleeding-edge-11.0-434871-20260916), and Proton-CachyOS-SLR (cachyos-11.0-20260703-slr) — identical crash on all three

I confirm

• [x] that I haven't found an existing compatibility report for this specific crash (there is an existing unofficial report, #9427, but it covers an unrelated symptom — mouse input not registering)
• [x] that I have checked whether there are updates for my system available

Symptoms

Game launches, gets to the Steam login step, then reliably crashes ~20 seconds in, every launch, on every Proton build tested.

Crash details

Exception 0xc0000005 (EXCEPTION_ACCESS_VIOLATION)
Access: Read
Address: 0x0000000000000060

Backtrace (from Proton Experimental official build, offsets from matching cachyos build in parentheses where they differ):

0 rsaenh.dll   +0x26432  (also seen at +0x32332 on a different Wine build)
1 rsaenh.dll   +0x5403   (also +0x6d2f)
2 advapi32.dll +0x10fa7  (also +0x13307)
3 FPXSteam.dll +0x4be69
4 FPXSteam.dll +0x1261d
5 FPXSteam.dll +0xe3aa
6 FPXSteam.dll +0x2b56e
7 FPXSteam.dll +0xc62de
8 kernel32.dll +0x11649
9 ntdll.dll    +0x10e0f

Faulting instruction at the crash site: callq *0x60(%rax) — an indirect call through what appears to be a null or uninitialized function pointer at offset 0x60 of some internal structure.

Analysis

FPXSteam.dll (the game's Steam-auth integration library) computes an HMAC using the legacy CryptoAPI (CryptCreateHash with CALG_HMAC, then CryptSetHashParam(HP_HMAC_INFO, ...) with HashAlgid = CALG_SHA_256). The crash happens inside rsaenh.dll's HMAC hash-init/update path.

I initially suspected this was the known issue where RSAENH_CPSetHashParam's CALG_HMAC case fails to find SHA-256 in a CSP's algorithm table and mis-reports success — but checking current Wine master (dlls/rsaenh/rsaenh.c), that specific path already guards against it:

pAlgInfo = get_algid_info(pCryptHash->hProv, pCryptHash->pHMACInfo->HashAlgid);
if (!pAlgInfo)
{
    FIXME("Hash algroithm %#x not found.\n", pCryptHash->pHMACInfo->HashAlgid);
    return FALSE;
}

Since the crash backtrace is past this point (inside the actual hash init/update calls that only run after pAlgInfo is found), the algorithm lookup is succeeding, and the null-pointer deref is happening somewhere inside the hash context setup/update itself — a distinct, apparently still-open bug.

I also tested a registry-based workaround (adding a duplicate PROV_RSA_FULL-type provider entry aliased to the AES-capable personality, to rule out CSP-selection as the cause). The crash was byte-for-byte identical with and without that change, which further supports this being a bug inside rsaenh.dll's HMAC code path itself rather than a CSP/personality selection issue.

Reproduction

1. Launch Aniimo through Steam (any recent Proton build).
2. Log in through the in-game Steam auth step.
3. Crash occurs ~20 seconds after launch, always at the same location.

Attachments

• crashinfo.txt from <library>/steamapps/compatdata/4126040/pfx/drive_c/users/steamuser/AppData/Local/Temp/Aniimo/Aniimo/Crashes/
• Full PROTON_LOG=1 Wine debug log (steam-4126040.log)

Happy to provide additional logs or test patches if anyone wants to dig further — this looks like a genuine crypto-provider bug in rsaenh.dll, not a GPU/driver/anticheat issue.

steam-4126040.log

crashinfo.txt