From b78737e8638412171fa996aac9c88cc47988a8ef Mon Sep 17 00:00:00 2001 From: Al Snow <43523+jasnow@users.noreply.github.com> Date: Wed, 19 Aug 2026 12:11:35 -0400 Subject: [PATCH 1/2] One new kobako gem advisory --- gems/kobako/GHSA-7pwq-q9jf-539h.yml | 48 +++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 gems/kobako/GHSA-7pwq-q9jf-539h.yml diff --git a/gems/kobako/GHSA-7pwq-q9jf-539h.yml b/gems/kobako/GHSA-7pwq-q9jf-539h.yml new file mode 100644 index 0000000000..75b5759390 --- /dev/null +++ b/gems/kobako/GHSA-7pwq-q9jf-539h.yml @@ -0,0 +1,48 @@ +--- +gem: kobako +cve: 2026-55107 +ghsa: 7pwq-q9jf-539h +url: https://github.com/elct9620/kobako/security/advisories/GHSA-7pwq-q9jf-539h +title: kobako Sandbox Escape - guest eval reaches host RCE via + method_missing → public_send (any bound Service) +date: 2026-08-18 +description: | + ### Summary + + A guest mruby script running inside the Kobako sandbox can execute + arbitrary Ruby in the host process, fully escaping the sandbox. + + ### Impact + + Complete sandbox escape leading to remote code execution in the host process, + defeating the gem's central guarantee of isolating untrusted mruby scripts. + Any deployment that runs untrusted or attacker-influenced scripts is affected. + All released versions (0.1.0 through 0.9.0) are vulnerable; the dispatcher + carried the same unguarded `public_send` sink under three successive names + (`registry` → `rpc` → `transport`). + + ### Credits + + Reported and fixed by Ahmed Al Hafoudh. +cvss_v3: 10.0 +patched_versions: + - ">= 0.9.1" +related: + url: + - https://rubygems.org/gems/kobako/versions/0.22.0 + - https://github.com/elct9620/kobako/releases/tag/v0.22.0 + - https://github.com/elct9620/kobako/commit/64f84700c81f44902bed9211318d5362f44987b3 + - https://advisories.gitlab.com/gem/kobako/CVE-2026-55107 + - https://github.com/elct9620/kobako/security/advisories/GHSA-7pwq-q9jf-539h + - https://github.com/advisories/GHSA-7pwq-q9jf-539h +notes: | + - cvss_v3 from GHSA + - CVE is reserved, but not published. + - Details on Patch: + - Fixed in 0.9.1. The dispatcher now rejects any method whose resolved + owner is a core/meta module (`BasicObject`, `Kernel`, `Object`, + `Module`, `Class`), so only methods the bound object itself defines — + or dynamically handles via `method_missing` — remain reachable. + The ambient reflection methods (`send`, `__send__`, `public_send`, + `instance_eval`, `instance_exec`, `method`, `instance_variable_get`, + …) are all owned by those modules and are blocked. From ce7301ce9d8bcd40cb26120bafa1e7d0773a64be Mon Sep 17 00:00:00 2001 From: Al Snow <43523+jasnow@users.noreply.github.com> Date: Wed, 19 Aug 2026 19:08:58 -0400 Subject: [PATCH 2/2] Update related URLs in GHSA-7pwq-q9jf-539h.yml --- gems/kobako/GHSA-7pwq-q9jf-539h.yml | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/gems/kobako/GHSA-7pwq-q9jf-539h.yml b/gems/kobako/GHSA-7pwq-q9jf-539h.yml index 75b5759390..3df887ccae 100644 --- a/gems/kobako/GHSA-7pwq-q9jf-539h.yml +++ b/gems/kobako/GHSA-7pwq-q9jf-539h.yml @@ -29,8 +29,9 @@ patched_versions: - ">= 0.9.1" related: url: - - https://rubygems.org/gems/kobako/versions/0.22.0 - - https://github.com/elct9620/kobako/releases/tag/v0.22.0 + - https://rubygems.org/gems/kobako/versions/0.9.1 + - https://github.com/elct9620/kobako/blob/main/CHANGELOG.md#091-2026-06-11 + - https://github.com/elct9620/kobako/commit/dd081665f368f7ba54e476c3ad045ee1aa8ed703 - https://github.com/elct9620/kobako/commit/64f84700c81f44902bed9211318d5362f44987b3 - https://advisories.gitlab.com/gem/kobako/CVE-2026-55107 - https://github.com/elct9620/kobako/security/advisories/GHSA-7pwq-q9jf-539h