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Fencer Vulns
medium 4.3

CVE-2026-86289 json

Ollama GGUF Decoder gguf.go readGGUFV1String integer overflow

published 2026-09-07 2 mo ago modified 2026-09-11 58 d ago also EUVD-2026-72306

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

A vulnerability was found in Ollama up to 0.31.1. This issue affects the function readGGUFV1String of the file fs/ggml/gguf.go of the component GGUF Decoder. Performing a manipulation results in integer overflow. The attack is possible to be carried out remotely. The exploit has been made public and could be used. Upgrading to version 0.31.2-rc1 is capable of addressing this issue. The patch is named 67b6a1c2d45321e0cb3c04a18073f9818de7724b. It is recommended to upgrade the affected component.

Patch / fix

  • n/a Ollama 0.31.2-rc1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-86289 updated cvss 4.3

github.com/ollama/ollama: Ollama: Denial of Service via Integer Overflow in GGUF Decoder

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
58 d ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ollama/ollama/issues/17033 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C
CNA 3.0 4.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C
CNA 4.0 2.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • n/a Ollama

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.