xyproto algernon up to 1.17.6 cross-domain policy

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability was found in xyproto algernon up to 1.17.6. It has been rated as problematic. The affected element is an unknown function. This manipulation causes cross-domain policy. This vulnerability is handled as CVE-2026-46431. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in xyproto algernon up to 1.17.6 and classified as problematic. Affected by this vulnerability is an unknown function. The manipulation with an unknown input leads to a cross-domain policy vulnerability. The CWE definition for the vulnerability is CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. As an impact it is known to affect confidentiality. The summary by CVE is:

Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server's Access-Control-Allow-Origin response header was hardcoded to the wildcard * regardless of the caller's Origin. Because EventSource does not preflight and does not send cookies, the wildcard is sufficient to let any third-party page the developer visits open a cross-origin EventSource to the SSE port and read the live filename stream from JavaScript. This vulnerability is fixed in 1.17.7.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-46431 since 05/14/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

Upgrading to version 1.17.7 eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross-domain policy
CWE: CWE-942 / CWE-346 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: algernon 1.17.7

Timelineinfo

05/14/2026 CVE reserved
05/26/2026 +12 days Advisory disclosed
05/26/2026 +0 days VulDB entry created
05/26/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-hw27-4v2q-5qff
Status: Confirmed

CVE: CVE-2026-46431 (🔒)
GCVE (CVE): GCVE-0-2026-46431
GCVE (VulDB): GCVE-100-365701

Entryinfo

Created: 05/26/2026 19:38
Changes: 05/26/2026 19:38 (63)
Complete: 🔍
Cache ID: 216::103

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