CVE-2026-54287 hono: AWS Lambda adapter merges multiple `Set-Cookie` headers into one value, dropping cookies on ALB single-header and Lattice
Hono framework incorrectly merges Set-Cookie headers on AWS Lambda, causing clients to drop cookies and potentially bypass authentication or session controls.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54287?
CVE-2026-54287 is a medium-severity vulnerability in honojs hono, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-116
Which versions are affected by CVE-2026-54287?
2 open source packages ship an affected version, including hono.
| Package | Affected | Fixed in |
|---|---|---|
hono npm | All versions | 4.12.25 |
hono npm | All versions | 4.12.25 |
How do I fix CVE-2026-54287?
Upgrade hono to 4.12.25 or later.
Is CVE-2026-54287 being exploited?
There is no known exploitation of CVE-2026-54287 in the wild and no public exploit code.
Sources
Also known as ECHO-55ba-b30a-0691, GHSA-j6c9-x7qj-28xf, MINI-2hgr-73jr-9f2r, MINI-2rjm-4g68-57c6, MINI-78g2-r3mc-p2p4, MINI-7vm2-xw2w-6ggp and 9 more.