5.3

CVE-2026-54287: honojs hono Improper Encoding or Escaping of Output

CVSS: 5.3v3.1MediumDeferred
AliasesGHSA-j6c9-x7qj-28xfCGA-22pv-9xf2-66hvCGA-29q4-5r6q-xqx6
Published 22-06-2026Last modified 22-06-2026
Open JSON

Vulnerability summary

CVE-2026-54287 is a medium (CVSS 5.3) Improper Encoding or Escaping of Output vulnerability in honojs hono. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.4% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.31%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-PQHX-35QG-HV6F

Timeline

  1. 22-06-2026
    PublishedVulnerability first disclosed.
  2. 22-06-2026
    Last modifiedVulnerability information updated.

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on AWS Lambda, the ALB single-header response and the VPC Lattice v2 response join multiple Set-Cookie headers into one comma-separated value. Because commas also appear inside cookie attributes (for example Expires dates), clients cannot split the value back into individual cookies and silently drop or misparse them. This vulnerability is fixed in 4.12.25.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.31%

Chance of exploitation in the next 30 days

Percentile

22%

Versus all other CVEs

30-day change

0.00 pp

From 0.31% on 19-09-2026

19-09-202619-10-2026
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

Chainguard25 products
  • commercial-gitlab-rails-ee-19.1< 19.1.7-r3
  • commercial-gitlab-rails-ee-19.2< 19.2.7-r1
  • commercial-gitlab-rails-ee-19.3< 19.3.3-r1
  • commercial-gitlab-rails-ee-19.4< 19.4.1-r1
  • commercial-gitlab-rails-ee-fips-19.1All versions (No fix recorded)
Honojs1 product
Npm1 product
  • hono< 4.12.25

3 vendors · 27 products

References

4 links