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CVE Record

CVE-2025-6021: Libxml2: integer overflow in xmlbuildqname() leads to stack buffer overflow in libxml2

A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2025-6021 is a high-severity libxml2 flaw that can crash software when crafted XML-related input triggers a stack buffer overflow. The direct business risk is availability loss in systems that process untrusted XML using affected Red Hat packages.

Executive priority

Treat as a high-priority availability risk for internet-facing or partner-facing XML-processing systems. It is not currently supported as known exploited in the provided evidence, but patching should be scheduled promptly because exploitation requires no authentication or user interaction.

Technical view

The flaw is in libxml2 xmlBuildQName(). Integer overflow during buffer-size calculation can lead to stack-based buffer overflow, memory corruption, or denial of service. The CVSS 3.1 vector is network exploitable with low complexity, no privileges, and no user interaction, but the listed impact is availability only.

Likely exposure

Exposure is most likely on Red Hat Enterprise Linux 7 ELS, 8, 9, 10, supported update streams, and OpenShift Container Platform 4.12 rhcos where vulnerable libxml2 packages are installed and parse untrusted input.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation. The CVSS vector indicates remote, unauthenticated triggering may be possible in applications that expose XML parsing paths to attacker-controlled input.

Researcher notes

Focus validation on reachable code paths into libxml2 xmlBuildQName(), especially QName construction from attacker-controlled XML content. The public bundle supports denial-of-service and memory-corruption impact, but does not establish confidentiality, integrity impact, exploit availability, or active exploitation.

Mitigation direction

  • Apply applicable Red Hat RHSA updates for affected RHEL and OpenShift products.
  • Prioritize externally reachable services that parse XML or XML-derived formats.
  • Reduce or block untrusted XML processing where patching is delayed.
  • Check non-Red Hat libxml2 deployments against their vendor advisories.
  • Track Red Hat errata for fixed package availability in each stream.

Validation and detection

  • Inventory libxml2 package versions across Linux hosts and container bases.
  • Map installed versions to the affected Red Hat versions in the CVE bundle.
  • Identify applications accepting XML or namespace-qualified input from networks or users.
  • Confirm RHSA updates are installed in RHEL and OpenShift images.
  • Monitor exposed XML-processing services for crashes or abnormal restarts.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CWE-787: Exact CWE lookup

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description · low confidence lookup

Container behavior lookup

The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2025-6021 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
5Timeline events
3ADP providers
29Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2025-6021Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineredhat

    Made public.

  2. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  3. Source timelineredhat

    Reported to Red Hat.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Unknown vendorlibxml2libxml2, 0unaffected
Red HatRed Hat Enterprise Linux 10libxml2, 0:2.12.5-7.el10_0affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supportlibxml2, 0:2.9.1-6.el7_9.10affected
Red HatRed Hat Enterprise Linux 8libxml2, 0:2.9.7-21.el8_10.1affected
Red HatRed Hat Enterprise Linux 8libxml2, 0:2.9.7-21.el8_10.1affected
Red HatRed Hat Enterprise Linux 8.2 Advanced Update Supportlibxml2, 0:2.9.7-9.el8_2.3affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportlibxml2, 0:2.9.7-9.el8_4.6affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onlibxml2, 0:2.9.7-9.el8_4.6affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportlibxml2, 0:2.9.7-13.el8_6.10affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicelibxml2, 0:2.9.7-13.el8_6.10affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionslibxml2, 0:2.9.7-13.el8_6.10affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicelibxml2, 0:2.9.7-16.el8_8.9affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionslibxml2, 0:2.9.7-16.el8_8.9affected
Red HatRed Hat Enterprise Linux 9libxml2, 0:2.9.13-10.el9_6affected
Red HatRed Hat Enterprise Linux 9libxml2, 0:2.9.13-10.el9_6affected
Red HatRed Hat Enterprise Linux 9.0 Update Services for SAP Solutionslibxml2, 0:2.9.13-1.el9_0.5affected
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutionslibxml2, 0:2.9.13-3.el9_2.7affected
Red HatRed Hat Enterprise Linux 9.4 Extended Update Supportlibxml2, 0:2.9.13-10.el9_4affected
Red HatRed Hat JBoss Core Services 2.4.62.SP2libxml2unaffected
Red HatRed Hat OpenShift Container Platform 4.12rhcos, 412.86.202509030110-0affected
Red HatRed Hat OpenShift Container Platform 4.13rhcos, 413.92.202509030117-0affected
Red HatRed Hat OpenShift Container Platform 4.14rhcos, 414.92.202508041909-0affected
Red HatRed Hat OpenShift Container Platform 4.15rhcos, 415.92.202508192014-0affected
Red HatRed Hat OpenShift Container Platform 4.16rhcos, 416.94.202508050040-0affected
Red HatRed Hat OpenShift Container Platform 4.17rhcos, 417.94.202508141510-0affected
Red HatRed Hat OpenShift Container Platform 4.18rhcos, 418.94.202508060022-0affected
Red HatRed Hat OpenShift Container Platform 4.19rhcos, 4.19.9.6.202507230107-0affected
Red HatRed Hat Discovery 2discovery/discovery-server-rhel9, 2.0.1-1754478727affected
Red HatRed Hat Hardened Imageslibxml2-main, 2.15.2-0.3.hum1affected
Red HatRed Hat Insights proxy 1.5insights-proxy/insights-proxy-container-rhel9, 1.5.5-1754504343affected
Weakness

CWE details

CWE-787

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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