Skip to content
Fencer Vulns
medium 5.3

CVE-2026-54287 json

Hono: AWS Lambda adapter merges multiple `Set-Cookie` headers into one value, dropping cookies on ALB single-header and Lattice

published 2026-06-16 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38326 , GHSA-j6c9-x7qj-28xf

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm hono 4.12.25
  • hono hono 4.12.25

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm hono
<4.12.25
4.12.25

Affected products

  • honojs hono

Classification

Weakness
  • CWE-116 Improper Encoding or Escaping of Output

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.