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CVE Record

CVE-2018-7753: An issue was discovered in Bleach 2.1.x before 2.1.3.

An issue was discovered in Bleach 2.1.x before 2.1.3. Attributes that have URI values weren't properly sanitized if the values contained character entities. Using character entities, it was possible to construct a URI value with a scheme that was not allowed that would slide through unsanitized.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Bleach is an HTML sanitization library. In affected 2.1.x versions before 2.1.3, specially encoded URI attribute values could bypass scheme filtering, allowing unsafe links to remain after sanitization.

Executive priority

Treat as a targeted dependency remediation item, not an emergency based on available evidence. Prioritize internet-facing or multi-user systems that render user-supplied HTML.

Technical view

The flaw concerns URI-valued attributes containing character entities. Bleach did not properly sanitize those values, so a URI scheme that should have been blocked could pass through unsanitized. The provided bundle does not include CVSS or CWE data.

Likely exposure

Exposure is most likely in applications using Bleach 2.1.x before 2.1.3 to clean untrusted HTML with URI-valued attributes. The bundle lists vendor/product/CPE fields as n/a, so dependency inventory is required.

Exploitation context

The provided bundle does not show active exploitation, and KEV is false. The issue is security-relevant where sanitized HTML is rendered to users, because unsafe URI schemes may survive filtering.

Researcher notes

Evidence identifies a sanitization bypass fixed in Bleach 2.1.3 with a related commit and Debian bug. No CVSS, CWE, or active exploitation details are provided in the bundle.

Mitigation direction

  • Upgrade Bleach 2.1.x installations to 2.1.3 or a later supported version.
  • Review the Bleach 2.1.3 release notes and downstream package guidance.
  • Prioritize systems that sanitize user-submitted HTML or rich text.
  • Add regression coverage for entity-encoded URI attributes and scheme filtering.

Validation and detection

  • Check dependency manifests and lockfiles for Bleach 2.1.x versions before 2.1.3.
  • Confirm production images and deployed environments use the remediated package version.
  • Review sanitizer configuration for URI-valued attributes and allowed schemes.
  • Verify tests reject encoded URI values that resolve to disallowed schemes.
Prepared
Confidence
medium
Sources
5

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

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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