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mistral.rs EUVDEUVD-2026-98092

| CVE-2026-108939 MEDIUM
Server-Side Request Forgery (SSRF) (CWE-918)
2026-10-12 VulDB GHSA-qjg5-pf8f-r356
5.5
CVSS 4.0 · Vendor: VulDB
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach remote media-URL endpoint
  2. Exploit
    Submit IPv6 transition address embedding internal IPv4
  3. Execution
    Bypass reject_private_ip filter
  4. Impact
    Server fetches internal/metadata service

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Credential Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires that the mistral.rs server exposes the media-source fetching feature (media_source.rs) which retrieves attacker-influenced remote URLs/addresses, with the reject_private_ip SSRF guard relied upon to block internal targets. The specific condition is supplying an IPv6 transition-address form that embeds an internal IPv4 - IPv4-mapped (::ffff:), IPv4-compatible (::x), 6to4 (2002::), or NAT64 (64:ff9b::) - which the pre-0.9.4 is_global_ip logic failed to decode, so the private/internal IP is treated as global and fetched. Limiting factors: the deployment must actually use remote media-URL fetching and be positioned where reachable internal services exist (e.g. cloud metadata, loopback, link-local); impact is limited to low confidentiality (internal response retrieval/probing), with no integrity or availability impact. No authentication is required per CVSS PR:N.

Impact

This is a moderate, credible-but-not-urgent issue. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N) describes a remotely reachable, low-complexity, unauthenticated flaw, but impact is deliberately scoped low: only VC:L with VI:N/VA:N and no subsequent-system impact (SC/SI/SA:N), reflecting that this SSRF primarily enables internal-service probing / limited read rather than full compromise. Exploit maturity is E:P (Proof-of-Concept), consistent with the description's statement that the exploit was publicly disclosed - so publicly available exploit code exists, but there is NO CISA KEV listing and NO EPSS score in the provided data, so real-world exploitation volume cannot be quantified. There is no SSVC decision data supplied. The signals are internally consistent (network vector matches an HTTP media-fetch SSRF; low confidentiality impact matches a filter-bypass that reaches internal addresses), so no contradiction needs flagging - the main caveat is that severity is capped by the limited technical impact and by the requirement that the target actually use the media-URL fetching feature. Treat as a prioritized patch for exposed mistral.rs deployments that accept remote media URLs, not a drop-everything emergency.

Exploit ScenarioDerived

An attacker sends a request to a mistral.rs server's media-fetching feature supplying an IPv6 transition address (e.g. 64:ff9b::a9fe:a9fe NAT64, 2002:7f00:1:: 6to4, or ::7f00:1 IPv4-compatible) that embeds an internal IPv4 such as 127.0.0.1 or 169.254.169.254. Because is_global_ip/reject_private_ip did not decode these embedded-IPv4 forms, the SSRF filter is bypassed and the server fetches from internal endpoints (e.g. cloud metadata). A public proof-of-concept exploit has been disclosed (CVSS E:P).

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 12, 2026

Server-side request forgery in EricLBuehler mistral.rs 0.9.3 and earlier allows remote unauthenticated attackers to bypass the private-IP guard used by the server's media-source fetcher, causing the server to request internal addresses such as loopback, link-local, or cloud metadata endpoints. The flaw lives in the is_global_ip/reject_private_ip logic in mistralrs-server-core/src/media_source.rs, which failed to decode IPv6 transition-address forms (IPv4-mapped, IPv4-compatible, 6to4, and NAT64) that embed an internal IPv4 address, so those addresses were judged global and fetched. Publicly available exploit code exists, and the issue is rated CVSS 4.0 6.9 (our independent assessment is a lower-severity SSRF with low confidentiality impact and no integrity or availability impact); no confirmed active exploitation (CISA KEV) was identified at time of analysis. Exploitation is only meaningful where remote media-URL fetching is enabled and reachable internal services exist.

RemediationAI

Vendor-released patch: 0.9.4 - upgrade mistral.rs to v0.9.4 (or apply the fix from commit cfb8c6a0c42361dc4579a9110b54d339c255b9fd / PR https://github.com/EricLBuehler/mistral.rs/pull/2446), which correctly decodes IPv6 transition addresses to their embedded IPv4 before the global-IP decision. If immediate upgrade is not possible, disable or restrict remote media-URL fetching in the server (do not accept user-supplied URLs or addresses for the media_source path) - the trade-off is loss of legitimate remote-media ingestion; alternatively run the server with egress firewall rules that deny RFC1918, loopback (127.0.0.0/8, ::1), link-local (169.254.0.0/16, fe80::/10), and cloud metadata endpoints (e.g. 169.254.169.254) - this is a compensating control that must be maintained in addition to patching because URL validation remains bypassable by unpatched instances. Also consider blocking outbound DNS resolution of attacker-controlled names that resolve to internal ranges (DNS rebinding) and requiring authentication on the media-fetch endpoint, since the flaw is reachable unauthenticated per CVSS PR:N. Track vendor advisory https://github.com/EricLBuehler/mistral.rs/releases/tag/v0.9.4 and the VulDB record https://vuldb.com/vuln/416763 for updates.

Affected VersionsENISA

Mistral.rs 0.9.1
Mistral.rs 0.9.2
Mistral.rs 0.9.3
Mistral.rs 0.9.0

Affected Packages

euvd mistral_rs no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The affected code is the URL/media fetching path of the mistral.rs inference server (mistralrs-server-core/src/media_source.rs), which accepts attacker-influenced remote URLs and relies on a reject_private_ip / is_global_ip check as an SSRF guard. This is CWE-918 (Server-Side Request Forgery): the guard's IPv6 handling only recognized IPv4-mapped addresses via to_ipv4_mapped(), so IPv4-compatible (::x.x.x.x), 6to4 (2002::/16), NAT64 well-known prefix (64:ff9b::/96), and local-use NAT64 (64:ff9b:1::/48) forms were treated as global IPv6 even though they embed a private IPv4 target. The upstream fix (commit cfb8c6a0c42361dc4579a9110b54d339c255b9fd, PR #2446) adds an embedded_ipv4 helper that extracts the embedded IPv4 from these transition ranges and judges it with is_global_ipv4, additionally rejects the 0.0.0.0/8 first-octet zero range and the local-use NAT64 prefix, and adds tests covering loopback, unspecified, and link-local embeddings. The vulnerability class is a canonicalization/normalization gap in IP address classification rather than a memory-safety issue; exploitation therefore depends on URL parsing and DNS/redirect behavior rather than on code execution.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulDB) PRIMARY 5.5 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
vuln.today AI 5.3 MEDIUM

Remote, unauthenticated request to the media-fetch endpoint with no user interaction (AV:N/AC:L/PR:N/UI:N); impact limited to internal-service reach so C:L, no integrity/availability, and no clear scope change asserted (S:U).

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

Primary rating from Vendor (VulDB).

CVSS VectorVendor: VulDB

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

1
CVSS changed
Oct 13, 2026 - 00:22 NVD
6.9 (MEDIUM) 5.5 (MEDIUM)

DescriptionCVE.org

A vulnerability has been found in EricLBuehler mistral.rs up to 0.9.3. Impacted is the function is_global_ip of the file mistralrs-server-core/src/media_source.rs. Such manipulation of the argument ip leads to server-side request forgery. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 0.9.4 is recommended to address this issue. The name of the patch is cfb8c6a0c42361dc4579a9110b54d339c255b9fd. The affected component should be upgraded.

Threat Intelligence Overview

EPSS Score
0.5%
Top 61% exploitable
Prevalence
Low
niche open-source Rust LLM inference engine, developer/research footprint
Data Quality
7 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.5%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.

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