CVE-2026-39909Public exploitNetwork attack vector

Remote code execution via stale graph recomputation

Published Aug 21, 2026 · Updated Aug 25, 2026

Use-after-free in llama.cpp's RPC GRAPH_RECOMPUTE handler allows remote attackers to execute code through stale graph replay. The server retains computation graphs after free_buffer releases their backing buffers, so later GRAPH_RECOMPUTE requests dereference attacker-reclaimable memory. TCP access to an unauthenticated ggml-rpc-server is sufficient; an upstream issue reproduces the flaw at b9994, so the published before-b8585 range is not reliable.

CVSS severity9.2
Critical
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in llama.cpp's RPC GRAPH_RECOMPUTE handler allows remote attackers to execute code through stale graph replay. The server retains computation graphs after free_buffer releases their backing buffers, so later GRAPH_RECOMPUTE requests dereference attacker-reclaimable memory. TCP access to an unauthenticated ggml-rpc-server is sufficient; an upstream issue reproduces the flaw at b9994, so the published before-b8585 range is not reliable.

The record

CVE
CVE-2026-39909
Published
Aug 21, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.1VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.2VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1210Exploitation of Remote Services

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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