PT-2026-21921 · Amazon+1 · Aws-Lambda+2

Edamame-X · Published 2026-02-25 · Updated 2026-03-02 · CVE-2026-27700

Positive Technologies (AI Summary)

CVSS v3.1

8.2

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Name of the Vulnerable Software and Affected Versions Hono versions 4.12.0 through 4.12.1

Description Hono is a Web application framework that provides support for any JavaScript runtime. When using the AWS Lambda adapter (hono/aws-lambda) behind an Application Load Balancer (ALB), the getConnInfo() function incorrectly selected the first value from the X-Forwarded-For header. Because AWS ALB appends the real client IP address to the end of the X-Forwarded-For header, the first value can be attacker-controlled. This could allow IP-based access control mechanisms, such as the ipRestriction middleware, to be bypassed. The X-Forwarded-For header is used to identify the originating IP address of a client connecting to a web server through an HTTP proxy or load balancer.

Recommendations Versions prior to 4.12.2 are affected. Update to version 4.12.2 or later to resolve this issue.

Exploit

Fix

Insufficient Verification of Data Authenticity

Authentication Bypass by Spoofing

Weakness Enumeration

CWE-345

CWE-290

Related Identifiers

CVE-2026-27700

GHSA-XH87-MX6M-69F3

Affected Products

Aws-Lambda

Aws Application Load Balancers

Hono

References · 15

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27700.json · Exploit
• https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3 · Vendor Advisory
• https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7 · Patch
• https://osv.dev/vulnerability/GHSA-xh87-mx6m-69f3 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-27700 · Security Note
• https://osv.dev/vulnerability/CVE-2026-27700 · Vendor Advisory
• https://github.com/honojs/hono · Note
• https://github.com/honojs/hono/releases/tag/v4.12.2 · Note
• https://twitter.com/CVEnew/status/2027744290382778413 · Twitter Post
• https://t.me/cveNotify/153476 · Telegram Post
• https://twitter.com/TheHackerWire/status/2026703742469558335 · Twitter Post
• https://t.me/cveNotify/153767 · Telegram Post
• https://twitter.com/infoflowcloud/status/2027744593287029248 · Twitter Post
• https://t.me/CVEtracker/45745 · Telegram Post
• https://twitter.com/CveTodo/status/2026698741642612993 · Twitter Post