CVE-2026-116816

llama.cpp b5899 before b10261 Heap Out-of-Bounds Write via plamo2 Tokenizer

Published Oct 27, 2026 CVSS 4.0 · 8.5 High EPSS < 1% KEV · Not listed

Description

llama.cpp b5899 before b10261 contains a heap out-of-bounds write vulnerability in llm_tokenizer_plamo2::build that allows attackers to corrupt heap memory via crafted GGUF models. Attackers can supply BYTE-typed token text like <0x-1> whose negative parsed value writes token ids before the bytes_ buffer during model loading, causing crashes or potential code execution.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

ggml-org

llama.cpp

unaffected

Version	Status	Constraints
`b5899`	affected	< b10261

No data.

Vendor Product Versions

Ggml

Llama.cpp

Version	Status	Scheme	Platform
`[b5899,b10261)`	affected	generic	—

Ggml-org

Llama.cpp

Version	Status	Scheme	Platform
`[b5899,b10261)`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.135% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
https://github.com/ggml-org/llama.cpp/blob/b10259/src/llama-vocab.cpp#L1376-L1377
https://github.com/ggml-org/llama.cpp/commit/cf06ad7dfe79e7bf2934150d4fefe1ce8db05490
https://github.com/ggml-org/llama.cpp/pull/25969
https://github.com/ggml-org/llama.cpp/pull/26511
https://github.com/ggml-org/llama.cpp/releases/tag/b10261
https://www.vulncheck.com/advisories/llama-cpp-b5899-before-b10261-heap-out-of-bounds-write-via-plamo2-tokenizer

History

Oct 31, 2026 3:30 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Oct 27, 2026 7:30 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Ggml-org Ggml-org llama.cpp
Vendors & Products		Ggml-org Ggml-org llama.cpp

Oct 27, 2026 4:30 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		llama.cpp b5899 before b10261 contains a heap out-of-bounds write vulnerability in llm_tokenizer_plamo2::build that allows attackers to corrupt heap memory via crafted GGUF models. Attackers can supply BYTE-typed token text like <0x-1> whose negative parsed value writes token ids before the bytes_ buffer during model loading, causing crashes or potential code execution.
Title		llama.cpp b5899 before b10261 Heap Out-of-Bounds Write via plamo2 Tokenizer
First Time appeared		Ggml Ggml llama.cpp
Weaknesses		CWE-129
CPEs		cpe:2.3:a:ggml:llama.cpp::::::::
Vendors & Products		Ggml Ggml llama.cpp
References		https://github.com/ggml-org/llama.cpp/blob/b10259/src/llama-vocab.cpp#L1376-L1377 https://github.com/ggml-org/llama.cpp/commit/cf06ad7dfe79e7bf2934150d4fefe1ce8db05490 https://github.com/ggml-org/llama.cpp/pull/25969 https://github.com/ggml-org/llama.cpp/pull/26511 https://github.com/ggml-org/llama.cpp/releases/tag/b10261 https://www.vulncheck.com/advisories/llama-cpp-b5899-before-b10261-heap-out-of-bounds-write-via-plamo2-tokenizer
Metrics		cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}` cvssV4_0 `{'score': 8.5, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}`