CVE ID :CVE-2026-43974<\/p>\n
Published : June 8, 2026, 2:12 p.m. | 21\u00a0minutes ago<\/p>\n
Description :Unexpected Status Code or Return Value vulnerability in ninenines gun (gun_http module) allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response.<\/p>\n
In gun_http:handle_inform\/8, when a 101 Switching Protocols response is received over HTTP\/1.1, the function verifies only that the Upgrade header is syntactically valid and that the stream reference is a plain reference(). It does not check whether the client ever sent an Upgrade or Connection: upgrade header on the corresponding request. Because this check is absent, any 101 response (solicited or not) causes gun to dispatch a gun_upgrade message to the caller and transition the entire connection to raw protocol mode.<\/p>\n
A malicious or compromised HTTP server can send an unsolicited 101 response to any HTTP\/1.1 request, causing the gun client to abandon HTTP framing for that connection. Once in raw mode, gun_raw applies no flow control (flow=infinity) and re-arms socket active mode after every received packet, so the server can flood the client with arbitrary bytes. These are forwarded as unbounded gun_data messages to the owner process, exhausting its mailbox and BEAM memory, ultimately crashing the VM.<\/p>\n
This issue affects gun: from 2.0.0 before 2.4.0.<\/p>\n
Severity: 8.7 | HIGH<\/p>\n
Visit the link for more details, such as CVSS details, affected products, timeline, and more…\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"
CVE ID :CVE-2026-43974 Published : June 8, 2026, 2:12 p.m. | 21\u00a0minutes ago Description :Unexpected Status Code or Return Value vulnerability in ninenines gun (gun_http module) allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response. In gun_http:handle_inform\/8, when a 101 Switching Protocols response is …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-79459","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/79459","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=79459"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/79459\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=79459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=79459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=79459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}