Inefficient Algorithmic Complexity vulnerability in the traversal engine in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU and memory via a flat run of sibling elements in sanitized HTML. The list clause of HtmlSanitizeEx.Traverser.traverse/2 recurses on the tail of a sibling list and then evaluates List.flatten([head] ++ tail) over the already flattened result, so every one of n siblings copies and re-walks the entire remaining tail. The flattening is only needed for the rare case where scrub returns several replacement nodes for one node, but the cost is paid across the whole tail at every step, making traversal quadratic in sibling count.
The traverser sits on every public entry point, so no particular scrubber or configuration is required and the payload needs only allowed tags. A 160 KB body of 20,000 sibling elements occupies a scheduler for roughly 1.7 seconds, and the cost grows faster than the body does.
This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.
References
| Link | Resource |
|---|---|
| https://cna.erlef.org/cves/CVE-2026-68750.html | Patch Third Party Advisory |
| https://github.com/rrrene/html_sanitize_ex/commit/9f5ccedbed230930813f992a1e6906fcf485981e | Patch |
| https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-463q-p2fr-mh9p | Broken Link |
| https://osv.dev/vulnerability/EEF-CVE-2026-68750 | Patch Third Party Advisory |
Configurations
History
11 Aug 2026, 13:42
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Rrrene
Rrrene htmlsanitizeex |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.5 |
| CPE | cpe:2.3:a:rrrene:htmlsanitizeex:*:*:*:*:*:*:*:* | |
| References | () https://cna.erlef.org/cves/CVE-2026-68750.html - Patch, Third Party Advisory | |
| References | () https://github.com/rrrene/html_sanitize_ex/commit/9f5ccedbed230930813f992a1e6906fcf485981e - Patch | |
| References | () https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-463q-p2fr-mh9p - Broken Link | |
| References | () https://osv.dev/vulnerability/EEF-CVE-2026-68750 - Patch, Third Party Advisory |
06 Aug 2026, 16:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-08-06 16:16
Updated : 2026-08-11 13:42
NVD link : CVE-2026-68750
Mitre link : CVE-2026-68750
CVE.ORG link : CVE-2026-68750
JSON object : View
Products Affected
rrrene
- htmlsanitizeex
CWE
CWE-407
Inefficient Algorithmic Complexity
