6.9

CVE-2026-109955: honojs hono Double Decoding of the Same Data

CVSS: 6.9v4.0MediumDeferred
AliasesRHSA-2026:84422RHSA-2026:84423RHSA-2026:84431
Published 13-10-2026Last modified 13-10-2026
Open JSON

Vulnerability summary

CVE-2026-109955 is a medium (CVSS 6.9) Double Decoding of the Same Data vulnerability in honojs hono. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.8% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.31%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 13-10-2026
    PublishedVulnerability first disclosed.
  2. 13-10-2026
    Last modifiedVulnerability information updated.

Description

Hono from 4.12.4 before 4.13.11 contains a middleware bypass vulnerability in serveStatic that allows unauthenticated attackers to skip prefix middleware by exploiting double path decoding. Attackers can send malformed percent-encoded paths that the router matches in encoded form, reaching static files without authentication checks running.

CVSS metrics

5 scores · 3 sources · 2 versions

EPSS trend

Probability

0.31%

Chance of exploitation in the next 30 days

Percentile

23%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

14-10-202619-10-2026
EPSS score
0.31%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Redhat3 products
  • grafana12.4< 0:12.4.12-0.5.hum1
  • grafana13.1< 0:13.1.7-0.2.hum1
  • grafana13.2< 0:13.2.3-0.2.hum1
Honojs1 product
  • hono≥ 4.12.4, < 4.13.11

2 vendors · 4 products

References

14 links
Show all 14 references