CVE-2026-55149Public exploitNetwork attack vectorHinoki check available

Authentication proxy crash via unbounded cookie allocation

Published Sep 15, 2026 · Updated Sep 15, 2026

Denial of service in Vouch Proxy before 0.48.0 allows remote attackers to crash the authentication proxy via a crafted cookie name. Cookie in pkg/cookie/cookie.go parses an attacker-controlled multipart count and passes it unchecked to make([]string, numParts), causing a fatal oversized heap allocation. The unauthenticated /validate and /_external-auth-:id paths reach this code before JWT validation, so one request interrupts the proxy and repeated requests sustain the outage.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Vouch Proxy before 0.48.0 allows remote attackers to crash the authentication proxy via a crafted cookie name. Cookie in pkg/cookie/cookie.go parses an attacker-controlled multipart count and passes it unchecked to make([]string, numParts), causing a fatal oversized heap allocation. The unauthenticated /validate and /_external-auth-:id paths reach this code before JWT validation, so one request interrupts the proxy and repeated requests sustain the outage.

The record

CVE
CVE-2026-55149
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Vouch
Product
Vouch Proxy
Classifications
CWE-789, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.48.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vouch · Vouch Proxyversion=< 0.48.0

Published CVSS scores

7.5GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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