{"id":"CVE-2026-66882","aliases":["EEF-CVE-2026-66882","EUVD-2026-65321","GHSA-54fc-x3hv-ffhw"],"status":"published","title":"Reflected XSS in AshAuthentication confirmation and magic link interaction forms","description":"Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.","severity":{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0075,"percentile":0.55272,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-08-25T08:03:47Z","modified":"2026-10-28T02:30:29Z","fixes":[{"ecosystem":"Hex","package":"ash_authentication","fixed_in":["4.14.2","5.0.0-rc.13"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Hex","package":"ash_authentication","ranges":[{"type":"SEMVER","events":[{"introduced":"4.8.0"},{"fixed":"4.14.2"}]},{"type":"SEMVER","events":[{"introduced":"5.0.0-rc.0"},{"fixed":"5.0.0-rc.13"}]}],"versions":["4.10.0","4.11.0","4.12.0","4.13.0","4.13.1","4.13.2","4.13.3","4.13.4","4.13.5","4.13.6","4.13.7","4.14.0","4.14.1","4.8.0","4.8.1","4.8.2","4.8.3","4.8.5","4.8.6","4.8.7","4.9.0","4.9.1","4.9.2","4.9.3","4.9.4","4.9.5","4.9.6","4.9.7","4.9.8","4.9.9","5.0.0-rc.0","5.0.0-rc.1","5.0.0-rc.10","5.0.0-rc.11","5.0.0-rc.12","5.0.0-rc.2","5.0.0-rc.3","5.0.0-rc.4","5.0.0-rc.5","5.0.0-rc.6","5.0.0-rc.7","5.0.0-rc.8","5.0.0-rc.9"]}],"products":[{"vendor":"team-alembic","product":"ash_authentication"}],"references":[{"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-54fc-x3hv-ffhw","tags":["vendor-advisory","related","exploit","advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-66882.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-66882","tags":["related","web"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/62719710790a150a9eacab9c0a066e0d122d15be","tags":["patch","fix"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/0bd5199db066be22b2ca1ec8bc6109e5d62e6070","tags":["patch","fix"]},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66882.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66882","tags":["advisory"]},{"url":"https://github.com/team-alembic/ash_authentication","tags":["package"]},{"url":"https://hex.pm/packages/ash_authentication","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-66882","title":"Reflected XSS in AshAuthentication confirmation and magic link interaction forms","description":"Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.","status":"published","published":"2026-08-25T08:03:47.721Z","modified":"2026-08-25T19:51:21.332Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:20:12.939084Z"}],"euvd":[{"id":"EUVD-2026-65321","description":"Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.","status":"published","published":"2026-08-25T08:03:47Z","modified":"2026-08-25T19:51:21Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"}],"updated_at":"2026-11-02T18:01:31.718552Z"}],"nvd":[{"id":"CVE-2026-66882","description":"Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.","status":"published","published":"2026-08-25T08:18:10.143Z","modified":"2026-09-01T21:15:00.147Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:41.018848Z"}],"osv":[{"id":"CVE-2026-66882","title":"Reflected XSS in AshAuthentication confirmation and magic link interaction forms","description":"Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.","status":"published","published":"2026-08-25T08:03:47.721Z","modified":"2026-10-28T02:30:29.813023746Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:14.46177Z"},{"id":"EEF-CVE-2026-66882","title":"Reflected XSS in AshAuthentication confirmation and magic link interaction forms","description":"## Summary\n\nImproper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with `require_interaction?` set to `true`, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's `value` attribute without HTML escaping: `lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex` interpolates the `confirm` parameter, and `lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex` interpolates the magic link token parameter. These templates are compiled with `EEx.function_from_file/3` using plain `\u003c%= %\u003e` expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. `AshAuthentication.AddOn.Confirmation.Plug.accept/2` only checks that a `confirm` key is present, and `AshAuthentication.Strategy.MagicLink.Plug.accept/2` reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a `\u003cscript\u003e` element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.\n\n## Configurations\n\nOnly strategies configured with `require_interaction?` set to `true` are affected. This option defaults to `false`, and when it is disabled the vulnerable accept route is not registered at all, so the affected pages cannot be reached.\n\nThe option is not obscure: AshAuthentication's own documentation for the confirmation add-on advises that applications using AshAuthenticationPhoenix should enable it, so the affected configuration is a documented and recommended deployment rather than an unusual one.\n\nAt least one of the following must be configured with `require_interaction? true`:\n\n- the `confirmation` add-on, which serves the affected confirmation accept form; or\n- the `magic_link` strategy, which serves the affected sign-in accept form.","status":"published","published":"2026-08-25T08:03:47.721Z","modified":"2026-09-08T04:15:03.796740656Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}