CVE-2020-10761Network attack vector

Authenticated server crash via oversized error reply

Published Jun 9, 2020 · Updated Aug 4, 2024

Reachable assertion in QEMU-KVM before 5.0.1 allows remote authenticated users to crash the qemu-nbd server with a long export name. During NBD option negotiation, nbd_negotiate_send_rep_verr appends a client-controlled, near-4096-byte missing export name to server text and asserts that the combined error remains below the protocol limit. The request must reach an NBD server and select a nonexistent export; TLS deployments require valid client credentials, and successful exploitation terminates that server process.

CVSS severity5.0
Medium
EPSS probability1.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in QEMU-KVM before 5.0.1 allows remote authenticated users to crash the qemu-nbd server with a long export name. During NBD option negotiation, nbd_negotiate_send_rep_verr appends a client-controlled, near-4096-byte missing export name to server text and asserts that the combined error remains below the protocol limit. The request must reach an NBD server and select a nonexistent export; TLS deployments require valid client credentials, and successful exploitation terminates that server process.

The record

CVE
CVE-2020-10761
Published
Jun 9, 2020
Updated
Aug 4, 2024
Vendor
Red Hat
Product
QEMU-KVM
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 9, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=all QEMU versions before QEMU 5.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · QEMU-KVMversion=all QEMU versions before QEMU 5.0.1

Published CVSS scores

5.0Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L
4.0NVDAV:N/AC:L/Au:S/C:N/I:N/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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