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Libslirp CVE-2020-7211

HIGH
Path Traversal (CWE-22)
2020-01-21 cve@mitre.org
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Path canonicalization, traversal prevention
MITRE ATT&CK

2 techniques across 2 tactics: Discovery, Collection

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

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could access files and directories outside the intended path by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 4.1% exploitation probability (EPSS)

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AnalysisAI

tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Path Traversal vulnerability could allow attackers to access files and directories outside the intended path.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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

Technical ContextAI · show details

This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows. Affected products include: Libslirp Project Libslirp, Qemu.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

DescriptionNVD

tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows.

Threat Intelligence Overview

EPSS Score
4.1%
Top 10% exploitable
Data Quality
2 sources
Confidence: Low

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 HIGH
CISA KEV No
Public POC No
EPSS 4.1%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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

42
Low Medium High Critical
KEV: 0
EPSS: +4
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.

Affected Products (CPE)NVD

cpe:2.3:a:libslirp_project:libslirp:4.1.0:*:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:4.2.0:*:*:*:*:*:*:*
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6.5 Apr 22

A use after free vulnerability in ip_reass() in ip_input.c of libslirp 4.2.0 and prior releases allows crafted packets t

CVE-2019-14378 HIGH POC
8.8 Jul 29

ip_reass in ip_input.c in libslirp 4.0.0 has a heap-based buffer overflow via a large packet because it mishandles a cas

CVE-2020-29130 MEDIUM POC
4.3 Nov 26

slirp.c in libslirp through 4.3.1 has a buffer over-read because it tries to read a certain amount of header data even i

CVE-2019-15890 HIGH
7.5 Sep 06

libslirp 4.0.0, as used in QEMU 4.1.0, has a use-after-free in ip_reass in ip_input.c. Rated high severity (CVSS 7.5), t

CVE-2026-9539 MEDIUM
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Out-of-bounds heap read and integer underflow in libslirp's TCP urgent data handler (sosendoob) exposes gigabytes of hos

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An out-of-bounds read vulnerability was found in the SLiRP networking implementation of the QEMU emulator. Rated medium

CVE-2020-8608 MEDIUM
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In libslirp 4.1.0, as used in QEMU 4.2.0, tcp_subr.c misuses snprintf return values, leading to a buffer overflow in lat

CVE-2020-7039 MEDIUM
5.6 Jan 16

tcp_emu in tcp_subr.c in libslirp 4.1.0, as used in QEMU 4.2.0, mismanages memory, as demonstrated by IRC DCC commands i

CVE-2020-29129 MEDIUM
4.3 Nov 26

ncsi.c in libslirp through 4.3.1 has a buffer over-read because it tries to read a certain amount of header data even if

CVE-2021-3595 LOW
3.8 Jun 15

An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. Rated low severity (CV

CVE-2021-3594 LOW
3.8 Jun 15

An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. Rated low severity (CV

CVE-2021-3593 LOW
3.8 Jun 15

An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. Rated low severity (CV

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