Buffer overflow in Ggml Llama.cpp
CVE-2026-70638
llama.cpp builds b1886 through b7445 contain an integer overflow vulnerability in the LLaMA-Android JNI wrapper where the new_1batch() function multiplies sizeof(llama_seq_id) by an attacker-controlled n_seq_max parameter without overflow validation, causing heap buffer allocation to wrap and allocate insufficient memory. Attackers can exploit this by providing a crafted n_seq_max value through a malicious model file or JNI call to trigger heap corruption and achieve denial of service or arbitrary code execution on Android applications using the LLaMA-Android binding.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (14.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Ggml Llama.cpp
- Ggml-Org Llama.cpp — versions b1886, 0.9.0, 5c0d18881e0e9794c96b2602736b758bac9d9388
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/Vladimir-tokarev-cyera/llama-cpp-security-patches (related, Patch, Third Party Advisory)
- github.com/ggml-org/llama.cpp/commit/5c0d18881e0e9794c96b2602736b758bac9d9388 (Patch, patch)
- github.com/ggml-org/llama.cpp/releases/tag/b7446 (release-notes, Patch, Release Notes, Vendor Advisory)
- www.vulncheck.com/advisories/llama-cpp-b1886-b7445-integer-overflow-via-new-1ba… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-70638?
- CVE-2026-70638 is a high-severity vulnerability in Ggml Llama.cpp, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-08-06.
- How severe is CVE-2026-70638?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2026-70638 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.