{"id":"CVE-2026-76949","title":"Authentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim's browser to replace that victim's authenticated session with one for the attacker's own…","summary":"Authentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim's browser to replace that victim's authenticated session with one for the attacker's own…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","cwe":["CWE-290"],"vendor":"team-alembic","product":"ash_authentication","affected":["ash_authentication >= 4.10.0 < 4.15.0","ash_authentication >= 5.0.0-rc.0 < 5.0.0-rc.14","team-alembic/ash_authentication >= 3d3de314692558d06ec13945f857f00514e95a8c < *"],"published":"2026-09-17","updated":"2026-09-18","sourceUpdated":"2026-09-18T18:16:18.527","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-76949","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-76949.html","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/3d3de314692558d06ec13945f857f00514e95a8c","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/9a34136b844abe179da1075067cf2835c64dcc12","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/b9568a53b438247238b1c5a4f49c8d84650f4bba","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-hh34-374j-pfr5","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-76949","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"tags":["nvd","cve.org"],"epss":0.00491,"epssPercentile":0.41279,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-09-18T14:24:28.652087Z"},"cvssSource":"cna","ingestedAt":"2026-09-17T22:30:21.406Z","slug":"CVE-2026-76949","body":"## Overview\n\nAuthentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim's browser to replace that victim's authenticated session with one for the attacker's own account.\n\nAshAuthentication.Plug.Helpers.sign_in_using_remember_me/3 skips re-authenticating an already-signed-in visitor by checking the session for \"<subject_name>_token\", but store_in_session/2 writes that key only when require_token_presence_for_authentication? is enabled and otherwise writes the bare subject name. At the default setting the guard therefore reads a key that is never written, its already-signed-in branch is unreachable, and the remember-me sign-in runs on every request through the per-request browser pipeline plug. A planted remember-me cookie is consequently honoured even for a visitor holding a live authenticated session, so whatever the victim enters afterwards lands in data the attacker controls. The read path in authenticate_resource_from_session/4 selects the key correctly, so the guard and the reader disagree about which key holds the session.\n\nThis issue affects ash_authentication: from 4.10.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}