CVE-2018-7753: mozilla bleach Improper Input Validation
Vulnerability summary
CVE-2018-7753 is a critical (CVSS 9.8) Improper Input Validation vulnerability in mozilla bleach. EPSS estimates a 2.17% chance of exploitation in the next 30 days, higher than 82.3% of scored vulnerabilities.
Severe, CVSS 9.8 (NVD); no exploitation reported by the 5 checked sources; EPSS 2% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 3Timeline
- 07-03-2018PublishedVulnerability first disclosed.
- 17-09-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
6 scores · 4 sources · 3 versions- OSV · PypiEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
2.17%
Chance of exploitation in the next 30 days
Percentile
82%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.17% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- python-bleach< 2.1.3-1
Mozilla1 product
- bleach2.1 | 2.1.1 | 2.1.2
PyPI1 product
- bleach≥ 2.1.0, < 2.1.3 | < c5df5789ec3471a31311f42c2d19fc2cf21b35ef | ≥ 2.1, < 2.1.3
Ubuntu1 product
- python-bleach< 2.1.2-1ubuntu0.1~esm1
4 vendors · 4 products
References
12 links- github.com/mozilla/bleach/commit/c5df5789ec3471a31311f42c2d19fc2cf21b35efX Refsource MISCPatchThird Party AdvisoryWEBFIXREPORT
- github.com/mozilla/bleachPACKAGE