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Fencer Vulns
critical 9.8

CVE-2018-7753 json

Bleach URI Scheme Restriction Bypass

published 2018-03-07 8 y ago modified 2026-06-17 4 mo ago also GHSA-m9mq-p2f9-cfqv , PYSEC-2018-51 , EUVD-2018-0026

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi bleach 2.1.3
  • python-bleach Debian 14, Debian 13, Debian 12 2.1.3-1

debian advisories DEBIAN-CVE-2018-7753

  • python-bleach Ubuntu Pro 18.04 LTS 2.1.2-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2018-7753

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-bleach openSUSE Tumbleweed 6.4.0-1.1
  • python-bleach openSUSE Tumbleweed 6.1.0-1.5

opensuse advisories openSUSE-SU-2026:11323-1openSUSE-SU-2024:14134-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-7753 updated cvss 5.3

python-bleach: URI Scheme Restriction Bypass with character entities

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.17% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi bleach
>=2.1.0, <2.1.3
>=2.1, <2.1.3
2.1.3

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.