CVE-2026-15997 Native ARM SHA3 / SHAKE `restoreFullState` fails to detect size_t underflow in a crafted encoded state
An integer underflow in ARM SHA3/SHAKE state restoration allows out-of-bounds writes, potentially leading to code execution or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-15997?
CVE-2026-15997 is a low-severity vulnerability in Legion of the Bouncy Castle Inc. BC-LTS, published on 16 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Out-of-bounds write vulnerability in Legion of the Bouncy Castle Inc. BC-LTS bcprov-lts8on on ARM allows Overflow Buffers.
This vulnerability is associated with program files https://github.Com/bcgit/bc-lts-java/blob/main/native_c/arm/sha/shake.C, https://github.Com/bcgit/bc-lts-java/blob/main/native_c/arm/sha/sha3.C.
This issue affects BC-LTS: from 2.73.0 before 2.73.12.1.
Issue is only applicable if application involved is accepting memoable SHA3 / SHAKE states from potentially untrusted sources.
Weakness: CWE-787
Which versions are affected by CVE-2026-15997?
How do I fix CVE-2026-15997?
No fix has been published for CVE-2026-15997 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-15997 being exploited?
There is no known exploitation of CVE-2026-15997 in the wild and no public exploit code.
Sources
Also known as GHSA-hcmw-xv23-7hqq, UBUNTU-CVE-2026-15997.