# CVE-2026-64439: linux: In the Linux kernel, the following vulnerability has been resolved:  crypto: krb5 - filter out async aead implementat...

CVE-2026-64439 is fixed in linux on 1 platform by DEBIAN-CVE-2026-64439 (version 7.1.4-1), released August 7, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-64439
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  crypto: krb5 - filter out async aead implementations at alloc  krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer).  When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion.  KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name:    BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7  The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site.  Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64439](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64439.md) | Aug 7, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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