VulnSocial

CVE-2026-27959Disclosure(koajs / koa)

LOWCVSS 7.5 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

Koa is middleware for Node.js using ES2017 async functions. Prior to versions 3.1.2 and 2.16.4, Koa's `ctx.hostname` API performs naive parsing of the HTTP Host header, extracting everything before the first colon without validating the input conforms to RFC 3986 hostname syntax. When a malformed Host header containing a `@` symbol is received, `ctx.hostname` returns `evil[.]com` - an attacker-controlled value. Applications using `ctx.hostname` for URL generation, password reset links, email verification URLs, or routing decisions are vulnerable to Host header injection attacks. Versions 3.1.2 and 2.16.4 fix the issue.

koajs CVEsBack to dashboard
0.0/ 10 priority

Sources & remediation

Patch / fix
Exploit / PoC references
Other references
Weakness type (CWE)
CWE-20

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • koa

Threat summary

  • 6 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Technical details provided in 6 signals
  • Disclosure: 5 classified signals
  • General: 1 classified signal
  • Peaked 2d ago at 4 mentions (2026-02-26); latest day: 1
  • 6 total mentions across 3 days

Affected systems

Vendors
koajs
Products
koa

Deep dive

Activity timeline6 mentions / 3d
01234Mentions · 2026-02-26: 4Mentions · 2026-02-27: 1Mentions · 2026-03-03: 1Technical Details · 2026-02-26: 4Technical Details · 2026-02-27: 1Technical Details · 2026-03-03: 102-2602-2703-03
Signal classification2 categories
Disclosure
583.3%
General
116.7%
Referenced assets5 URLs
Classification over time
DateTotalLabels
2026-02-264
Disclosure4
2026-02-271
Disclosure1
2026-03-031
General1
Full discourse6 posts
  • CRAC Learning - Tech@cracbot
    General

    CVE-2026-27959 (CVSS:7.5, HIGH) is Analyzed. Koa is middleware for Node.js using ES2017 async functions. Prior to versions 3.1.2 and 2.16.4, Koa's `ctx.hostname` API..https://nvd.nist.gov/vuln/detail/CVE-2026-27959 #cybersecurityawareness #cybersecurity #CVE #infosec #hacker #nvd #mitre

    Post summary

    The post references CVE-2026-27959, noting its CVSS score and affected Koa versions, but provides no PoC, exploit, patch, or active exploitation details.

    0000021
    173 followersView on X
  • cvereports@_cvereports
    Disclosure

    CVE-2026-27959: Hostile Takeover: Dissecting Koa's Host Header Injection A high-severity Host Header Injection vulnerability in the popular Node.js framework Koa allows attackers to manipulate context.hostname via malformed headers. By exploiting Koa'... https://cvereports.com/reports/CVE-2026-27959

    Post summary

    The report announces a high‑severity Host Header Injection vulnerability in the Koa framework that permits manipulation of context.hostname through malformed headers, but no PoC, exploit, or patch information is provided.

    0000040
    32 followersView on X
  • mysocAi@MysocAi
    Disclosure

    [HIGH] Koa Vulnerability Enables Host Header Injection CVE-2026-27959 allows manipulation of password reset URLs. CVE: CVE-2026-27959 • APT: Unknown • Status: ACTIVE Web applications at risk. #mysocAi #CyberSecu… https://www.cybersecbrief.com/news/cybersec/cybersec-2026-02-26

    Post summary

    The post announces CVE-2026-27959, a host header injection vulnerability in Koa that enables manipulation of password reset URLs, highlighting the risk to web applications.

    000002
    3 followersView on X
  • mysocAi@MysocAi
    Disclosure

    [HIGH] Koa Host Header Injection Vulnerability CVE-2026-27959 enables malicious URL generation via userinfo-based host header injection. CVE: CVE-2026-27959 • APT: Unknown • Status: ACTIVE Web applications vulner… https://www.cybersecbrief.com/news/cybersec/cybersec-2026-02-26

    Post summary

    The article announces a new host header injection vulnerability (CVE‑2026‑27959) that enables malicious URL generation via userinfo‑based host header injection, but it does not provide a PoC, exploit code, or patch details.

    000000
    3 followersView on X
  • CVE@CVEnew
    Disclosure

    CVE-2026-27959 Koa is middleware for Node.js using ES2017 async functions. Prior to versions 3.1.2 and 2.16.4, Koa's `ctx.hostname` API performs naive parsing of the HTTP Host heade… https://www.cve.org/CVERecord?id=CVE-2026-27959

    Post summary

    CVE-2026-27959 describes a vulnerability in Koa's ctx.hostname API where naive parsing of the HTTP Host header can lead to issues, affecting versions prior to 3.1.2 and 2.16.4.

    00000103
    56.6K followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    Disclosure

    CVE-2026-27959 Host Header Injection in Koa Middleware Affecting URL Generation and Routing https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-27959

    Post summary

    A new host header injection vulnerability (CVE-2026-27959) affecting Koa middleware has been disclosed, with details available on Vulmon.

    0000035
    4.0K followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appkoajskoa-node.js-

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