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CVE Record

CVE-2026-25679: Incorrect parsing of IPv6 host literals in net/url

url.Parse insufficiently validated the host/authority component and accepted some invalid URLs.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Go applications that parse untrusted URLs may accept malformed IPv6 host syntax as valid. If business logic depends on URL parsing for routing, filtering, allowlists, proxying, or security decisions, an attacker-supplied URL could be handled differently than intended. The public bundle rates this high because remote, unauthenticated input can affect availability.

Executive priority

Prioritize assessment for internet-facing Go services that parse user-supplied URLs. The issue is high severity but currently lacks supplied evidence of active exploitation, so response should be prompt, risk-based patching rather than emergency incident handling.

Technical view

CVE-2026-25679 affects Go standard library net/url. url.Parse insufficiently validated the host/authority component and accepted some invalid URLs involving IPv6 host literals. The supplied CVSS is 7.5 with network attack vector, low complexity, no privileges, no user interaction, and availability impact only.

Likely exposure

Exposure is most likely in Go services that call net/url on untrusted URLs, especially gateways, proxies, crawlers, webhook handlers, redirect logic, and policy enforcement code. Exact vulnerable Go release ranges and downstream product status should be verified against Go and vendor advisories.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. Treat exploitation as plausible where attacker-controlled URLs reach parsing-dependent security or routing decisions, but do not assume exploitation is occurring without additional evidence.

Researcher notes

Focus analysis on discrepancies between accepted and valid host/authority syntax in net/url. The supplied data supports availability impact, not confidentiality or integrity impact. Evidence is incomplete on exact fixed versions and downstream package scope, so rely on Go and Red Hat source advisories for final exposure calls.

Mitigation direction

  • Check Go advisory GO-2026-4601 for fixed Go versions.
  • Apply relevant Go standard library updates when available.
  • Apply Red Hat errata where affected downstream packages are used.
  • Review URL parsing security controls for malformed IPv6 literals.
  • Add rejection logic for invalid host/authority input if vendor updates are pending.

Validation and detection

  • Inventory Go services that parse externally supplied URLs.
  • Identify Go toolchain versions used to build deployed services.
  • Compare deployed versions with GO-2026-4601 and vendor advisories.
  • Test whether security logic accepts malformed IPv6 host literals.
  • Confirm patched builds are redeployed, not only build images updated.
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 · low confidence lookup

CWE-1286: Exact CWE lookup

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cve · low confidence lookup

CVE-2026-25679 mapping review

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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.

2CVSS vectors
5Timeline events
2ADP providers
45Source links

SSVC decision data

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

CVSS vector scores

2 official scores

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

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-25679Attack 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. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

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

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPnet/url: Incorrect parsing of IPv6 host literals in net/url
other:Red Hat severity ratingcvssV3_1
  • 2026-03-06T22:02:11.567Z: Reported to Red Hat.
  • 2026-03-06T21:28:14.211Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Go standard librarynet/urlnet/url, 0, 1.26.0-0unaffected
Weakness

CWE details

CWE-1286

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

CWE-1286 · source CWE mapping

Improper Validation of Syntactic Correctness of Input

Improper Validation of Syntactic Correctness of Input represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs