Is there a patch available for CVE-2026-15997?

Yes, a patch is available for CVE-2026-15997. Update the affected software to the latest version immediately.

BC-LTS bcprov CVE-2026-15997

Q: What is the CVSS score of CVE-2026-15997?

CVE-2026-15997 has a CVSS 4.0 base score of 1.7 (Low). CVSS vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:P/AU:N/R:A/V:D/RE:M/U:Amber. EPSS exploitation probability: 0.1%.

EUVD-2026-45068 LOW

Out-of-bounds Write (CWE-787)

2026-07-16 bcorg

GHSA-hcmw-xv23-7hqq

Buffer Overflow Java Memory Corruption Bc Lts Legion Of The Bouncy Castle Inc

1.7

CVSS 4.0 · Vendor: bcorg

Severity by source

Vendor (bcorg) PRIMARY

1.7 LOW

CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:P/AU:N/R:A/V:D/RE:M/U:Amber

vuln.today AI

4.7 MEDIUM

Local vector and high complexity reflect ARM-only native code path and mandatory memoable-state feature exposure; no integrity or availability impact is asserted; confidentiality impact aligns with official CVSS 4.0 VC:H rating.

3.1 AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

4.0 AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (bcorg).

CVSS VectorVendor: bcorg

Attack Vector

Local

Attack Complexity

High

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Patch available

Jul 17, 2026 - 02:32 EUVD

Analysis Generated

Jul 16, 2026 - 22:46 vuln.today

DescriptionCVE.org

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.

AnalysisAI

Out-of-bounds write in Bouncy Castle BC-LTS bcprov-lts8on affects ARM deployments running versions 2.73.0 through 2.73.12.0, with high confidentiality impact if successfully exploited. The flaw resides in ARM-specific native C implementations of SHA3 and SHAKE algorithms and is only triggered when an application accepts memoable SHA3/SHAKE cryptographic states from potentially untrusted external sources. No public exploit code exists and no active exploitation has been confirmed at time of analysis; the CVSS 4.0 score of 1.7 reflects the very narrow exploitation conditions required to reach this code path.

Technical ContextAI

The vulnerability exists in native ARM C code within the BC-LTS Java cryptography library, specifically in native_c/arm/sha/shake.c and native_c/arm/sha/sha3.c. These files provide ARM-optimized implementations of the SHA-3 family of hash functions, including SHAKE128 and SHAKE256 extendable-output functions. The root cause is CWE-787 (Out-of-Bounds Write), a memory safety flaw where data is written beyond the bounds of an allocated buffer. The SHA3/SHAKE implementation in BC-LTS supports a 'memoable' state interface - a mechanism to serialize and restore the internal cryptographic state of a running hash operation. If a maliciously crafted state blob is supplied to the restore path on an ARM host, the native layer can write outside its allocated buffer, potentially corrupting adjacent memory in a way that results in confidentiality compromise of adjacent data. The affected CPE is cpe:2.3:a:legion_of_the_bouncy_castle_inc.:bc-lts:*:*:*:*:*:*:*:*. Non-ARM platforms use separate code paths and are not affected.

RemediationAI

The primary remediation is to upgrade BC-LTS bcprov-lts8on to version 2.73.12.1 or later, which resolves the out-of-bounds write in the ARM SHA3/SHAKE native code. Full upgrade guidance is available in the vendor advisory at https://github.com/bcgit/bc-lts-java/wiki/CVE-2026-15997. If immediate upgrade is not feasible, the most effective and targeted compensating control is to audit application code and ensure that no SHA3/SHAKE memoable state objects sourced from untrusted or externally-controlled inputs are accepted or processed - the CVE description explicitly limits exposure to this code path. Applications that use BC-LTS SHA3/SHAKE only for standard hashing (not memoable state save/restore), or that only restore state from internally-trusted sources, are not exposed regardless of the deployed version. Restricting or removing the API surface that accepts encoded SHA3/SHAKE state from untrusted callers carries minimal functional trade-off for most deployments and is a well-scoped, low-risk interim measure until the patch can be applied.