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CVE Record

CVE-2026-6253: proxy credentials leak over redirect-to proxy

curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy

MediumCVSS 5.9Not KEV-listedUpdated
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Potential ATT&CK relevance

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ATT&CK lookup starting points

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cwe · medium confidence lookup

CWE-522: Credential and account abuse lookup

Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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CVE-2026-6253 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.9 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/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
3Timeline events
2ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical 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
5.9CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H2.23.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.9Medium
CVSS 3.1 vector shape for CVE-2026-6253Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/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. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
curlcurl7.14.1, 8.15.0, 8.17.0unaffected
curlcurl3b60bb725913ce7339aefef0a14b12df4c24db60unaffected
curlcurl8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1, 8.11.0, 8.10.1, 8.10.0, 8.9.1, 8.9.0, 8.8.0, 8.7.1, 8.7.0, 8.6.0, 8.5.0, 8.4.0, 8.3.0, 8.2.1, 8.2.0, 8.1.2, 8.1.1, 8.1.0, 8.0.1, 8.0.0, 7.88.1, 7.88.0, 7.87.0, 7.86.0, 7.85.0, 7.84.0, 7.83.1, 7.83.0, 7.82.0, 7.81.0, 7.80.0, 7.79.1, 7.79.0, 7.78.0, 7.77.0, 7.76.1, 7.76.0, 7.75.0, 7.74.0, 7.73.0, 7.72.0, 7.71.1, 7.71.0, 7.70.0, 7.69.1, 7.69.0, 7.68.0, 7.67.0, 7.66.0, 7.65.3, 7.65.2, 7.65.1, 7.65.0, 7.64.1, 7.64.0, 7.63.0, 7.62.0, 7.61.1, 7.61.0, 7.60.0, 7.59.0, 7.58.0, 7.57.0, 7.56.1, 7.56.0, 7.55.1, 7.55.0, 7.54.1, 7.54.0, 7.53.1, 7.53.0, 7.52.1, 7.52.0, 7.51.0, 7.50.3, 7.50.2, 7.50.1, 7.50.0, 7.49.1, 7.49.0, 7.48.0, 7.47.1, 7.47.0, 7.46.0, 7.45.0, 7.44.0, 7.43.0, 7.42.1, 7.42.0, 7.41.0, 7.40.0, 7.39.0, 7.38.0, 7.37.1, 7.37.0, 7.36.0, 7.35.0, 7.34.0, 7.33.0, 7.32.0, 7.31.0, 7.30.0, 7.29.0, 7.28.1, 7.28.0, 7.27.0, 7.26.0, 7.25.0, 7.24.0, 7.23.1, 7.23.0, 7.22.0, 7.21.7, 7.21.6, 7.21.5, 7.21.4, 7.21.3, 7.21.2, 7.21.1, 7.21.0, 7.20.1, 7.20.0, 7.19.7, 7.19.6, 7.19.5, 7.19.4, 7.19.3, 7.19.2, 7.19.1, 7.19.0, 7.18.2, 7.18.1, 7.18.0, 7.17.1, 7.17.0, 7.16.4, 7.16.3, 7.16.2, 7.16.1, 7.16.0, 7.15.5, 7.15.4, 7.15.3, 7.15.2, 7.15.1, 7.15.0, 7.14.1unaffected
Weakness

CWE details

CWE-522

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