Is the Copy Fail (CVE-2026-31431) vulnerability already patched in Fedora 43?

Ask Fedora
1

Title. Someone commented here that it was patched in kernel 6.19.12, but I’m not sure how to verify that.

2

What do you mean by “verify”? If you don’t trust Adam on this, click on the kernel-ml link in the bz. If you don’t trust GKH, try the exploit. It’s all linked from the BZ which you linked.

3

You take a look at the changelog for 6.19.12 and notice this text, particularly the upstream commit:

commit ce42ee423e58dffa5ec03524054c9d8bfd4f6237
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Thu Mar 26 15:30:20 2026 +0900

    crypto: algif_aead - Revert to operating out-of-place
    
    [ Upstream commit a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5 ]
    
    This mostly reverts commit 72548b093ee3 except for the copying of
    the associated data.
    
    There is no benefit in operating in-place in algif_aead since the
    source and destination come from different mappings.  Get rid of
    all the complexity added for in-place operation and just copy the
    AD directly.
    
    Fixes: 72548b093ee3 ("crypto: algif_aead - copy AAD from src to dst")
    Reported-by: Taeyang Lee <0wn@theori.io>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: Sasha Levin <sashal@kernel.org>

Or, as @mjg suggested, you try the exploit code, it’s 10 lines of Python code and it is deterministic. Takes less than 30s to paste it into a file and run it, less if you are willing to pipe curl output straight into python3 (but anyone willing to do that probably doesn’t need to worry about Copy Fail, frankly).