# 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.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 27 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-94071, BELL-CVE-2026-64544, DEBIAN-CVE-2026-64544, GHSA-4qp2-jghx-88mp, UBUNTU-CVE-2026-64544

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64544 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-64544 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64544/ (Markdown: https://insights.sbomify.com/CVE-2026-64544/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64544
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64544
- OSV: https://osv.dev/vulnerability/CVE-2026-64544

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64544/
Summaries are generated and may contain mistakes; the official description above is the record.