BlackTreeCVE Intelligence
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Full vulnerability report · 2020
CVE-2020-25637High confidence

This flaw affects the polkit access control driver

Unknown · libvirt

6.7MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Low, lowered one band.downgradedsince 4 Aug 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.53% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Unknown libvirt and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: No default targetRemediation target: Normal maintenance

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Alpine, Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

7 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · communitylibvirtVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.6.8.0-r0Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.22v3.22 · communitylibvirtVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.6.8.0-r0Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.21v3.21 · communitylibvirtVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.6.8.0-r0Alpine Security Database ↗Source updated 19 Aug 2026
Debian trixietrixie · sourcelibvirtVendor fix publishedDebian records a fixed source-package version for this release.6.8.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcelibvirtVendor fix publishedDebian records a fixed source-package version for this release.6.8.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcelibvirtVendor fix publishedDebian records a fixed source-package version for this release.6.8.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcelibvirtVendor fix publishedDebian records a fixed source-package version for this release.6.8.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-18305

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

A double free memory issue was found to occur in the libvirt API, in versions before 6.8.0, responsible for requesting information about network interfaces of a running QEMU domain. This flaw affects the polkit access control driver. Specifically, clients connecting to the read-write socket with limited ACL permissions could use this flaw to crash the libvirt daemon, resulting in a denial of service, or potentially escalate their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

What

A double free memory issue was found to occur in the libvirt API, in versions before 6.8.0, responsible for requesting information about network interfaces of a running QEMU domain. This flaw affects the polkit access control driver. Specifically, clients connecting to the read-write socket with limited ACL permissions could use this flaw to crash the libvirt daemon, resulting in a denial of service, or potentially escalate their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Why

The product calls free() twice on the same memory address.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

What

A double free memory issue was found to occur in the libvirt API, in versions before 6.8.0, responsible for requesting information about network interfaces of a running QEMU domain. This flaw affects the polkit access control driver. Specifically, clients connecting to the read-write socket with limited ACL permissions could use this flaw to crash the libvirt daemon, resulting in a denial of service, or potentially escalate their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Why

The product calls free() twice on the same memory address.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Double Free → disrupt the affected service
Attack surface
Local
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-415 ↗

CWE-415: Double Free. The product calls free() twice on the same memory address.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
Denial of serviceCWE-415
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2022-1724libvirt: Schwachstelle ermöglicht Denial of Service

Ein lokaler Angreifer kann eine Schwachstelle in libvirt ausnutzen, um einen Denial of Service Zustand herbeizuführen oder um seine Privilegien zu erhöhen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20201007Security Bulletin 07 Oct 2020

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 07 Oct 2020, published on 7 October 2020. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-267Multiples vulnérabilités dans Juniper Networks Junos Space

ecord?id=CVE-2020-14385 Référence CVE CVE-2020-15705 https://www.cve.org/CVERecord?id=CVE-2020-15705 Référence CVE CVE-2020-15706 https://www.cve.org/CVERecord?id=CVE-2020-15706 Référence CVE CVE-2020-15707 https://www.cve.org/CVERecord?id=CVE-2020-15707 Référence CVE CVE-2020-15999 https://www.cve.org/CVERecord?id=CVE-2020-15999 Référence CVE CVE-2020-1749 https://www.cve.org/CVERecord?id=CVE-2020-1749 Référence CVE CVE-2020-1983 https://www.cve.org/CVERecord?id=CVE-2020-1983 Référence CVE CVE-2020-24394 https://www.cve.org/CVERecord?id=CVE-2020-24394 Référence CVE CVE-2020-25212 https://www.cve.org/CVERecord?id=CVE-2020-25212 Référence CVE CVE-2020-25637 https://www.cve.org/CVERecord?id=CVE-2020-25637 Référence CVE CVE-2020-25643 https://www.cve.org/CVERecord?id=CVE-2020-25643 Référence CVE CVE-2020-2732 https://www.cve.org/CVERecord?id=CVE-2020-2732 Référence CVE CVE-2020-5208 https://www.cve.org/CVERecord?id=CVE-2020-5208 Référence CVE CVE-2020-6829 https://www.cve.org/CVERecord?id=CVE-2020-6829 Référence CVE CVE-2020-7039 https://www.cve.org/CVERecord?id=CVE-2020-7039 Référence CVE CVE-2020-8647 https://www.cve.org/CVERecord?id=CVE-2020-8647 Référence CVE CVE-2020-8649 https://www.cve.org/CVERecord?id=CVE-2020-8649 Référence CVE CVE-2020-9383 https://www.cve.org/CVERecord?id=CVE-2020-9383

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-011893libvirt API における二重解放に関する脆弱性

libvirt API には、二重解放に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
libvirt: libvirt versions before 6.8.0
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 6 Oct 2020 · Last source change 4 Aug 2024, 15:40 UTC · CWE-415 · Double Free

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-18305
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2020-18305↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-25637 · cve.blacktree.nl