CVE-2026-104477: showdownjs showdown Cross-site Scripting
Vulnerability summary
CVE-2026-104477 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in showdownjs showdown. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 7.9% of scored vulnerabilities.
Timeline
- 02-10-2026PublishedVulnerability first disclosed.
- 05-10-2026Last modifiedVulnerability information updated.
Description
Showdown through 2.1.0 contains a cross-site scripting vulnerability in the makehtml link and image subparsers, which fail to escape double quotes in destination URLs placed into href and src attributes. Attackers can craft markdown links or images containing a double quote followed by onerror or onmouseover handlers to execute script when victims view rendered HTML.
CVSS metrics
4 scores · 2 sources · 2 versions- NVDNIST5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST6.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
8%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Showdownjs1 product
- showdown≤ 2.1.0
1 vendor · 1 product
References
3 links- www.vulncheck.com/advisories/…Third Party Advisory