CVE-2026-64544 crypto: asymmetric_keys - fix OOB read in pefile_digest_pe_contents
A local attacker can trigger a kernel panic via integer underflow in PE file signature verification, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64544?
CVE-2026-64544 is a vulnerability in Linux, published on 27 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
crypto: asymmetric_keys - fix OOB read in pefile_digest_pe_contents
pefile_digest_pe_contents() computes the trailing-data hash length as pelen - (hashed_bytes + certs_size). A crafted PE can make the addition exceed pelen, causing the unsigned subtraction to underflow to ~4 GiB. This is passed to crypto_shash_update() which reads out of bounds and panics on unmapped vmalloc guard pages.
BUG: unable to handle page fault for address: ffffc900038d8000 Oops: Oops: 0000 [#1] SMP KASAN NOPTI RIP: 0010:sha256_blocks_generic (lib/crypto/sha256.c:152) Call Trace: <TASK> __sha256_update (lib/crypto/sha256.c:208) crypto_sha256_update (crypto/sha256.c:142) verify_pefile_signature (crypto/asymmetric_keys/verify_pefile.c:436) kexec_kernel_verify_pe_sig (kernel/kexec_file.c:151) __do_sys_kexec_file_load (kernel/kexec_file.c:406) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> Kernel panic - not syncing: Fatal exception
Validate that the addition does not overflow and the result does not exceed pelen before the subtraction. Return -ELIBBAD on failure.
Which versions are affected by CVE-2026-64544?
How do I fix CVE-2026-64544?
Apply the vendor's patch.
Is CVE-2026-64544 being exploited?
There is no known exploitation of CVE-2026-64544 in the wild and no public exploit code.
Sources
Also known as AZL-94071, BELL-CVE-2026-64544, DEBIAN-CVE-2026-64544, GHSA-4qp2-jghx-88mp, UBUNTU-CVE-2026-64544.