CVE-2026-81637 (GCVE-0-2026-81637)

Vulnerability from cvelistv5 – Published: 2026-09-17 13:09 – Updated: 2026-09-17 18:26
VLAI
Title
Replayable OAuth2 CSRF state retained after a failed callback in AshAuthentication
Summary
Insufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim's OAuth2 state value to replay the callback and sign that victim into an attacker-controlled account. AshAuthentication.Strategy.OAuth2.Plug.callback/2 clears the stored session_params through a rebinding step inside its with chain, conn <- delete_session(conn, session_key). Elixir evaluates the else block in the scope enclosing the with, so every failure path (the provider returning ?error=access_denied, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches store_authentication_result/2 holding the original connection and the session entry is never removed. The value the module's own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry. This issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
Severity
2.3 (Low)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-17 18:26 UTC
CWE
  • CWE-613 - Insufficient Session Expiration
Assigner
EEF CNA under the mitre root
CNA scorecard A 97/100 over 357 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
team-alembic ash_authentication Affected: 0.6.0 , < 4.15.0 (semver)
Affected: 5.0.0-rc.0 , < 5.0.0-rc.14 (semver)
    cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*
Create a notification for this product.
team-alembic ash_authentication Affected: c5f589058e04239263f50a1430eb17ea6d5dd1a2 , < * (git)
    cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Peter Ullrich Jonatan Männchen / EEF James Harton
Show details on NVD website
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    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-81637",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-09-17T18:26:48.969731Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-09-17T18:26:54.773Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "collectionURL": "https://repo.hex.pm",
              "cpes": [
                "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
              ],
              "defaultStatus": "unaffected",
              "modules": [
                "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027"
              ],
              "packageName": "ash_authentication",
              "packageURL": "pkg:hex/ash_authentication",
              "product": "ash_authentication",
              "programFiles": [
                "lib/ash_authentication/strategies/oauth2/plug.ex"
              ],
              "programRoutines": [
                {
                  "name": "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027:callback/2"
                },
                {
                  "name": "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027:request/2"
                }
              ],
              "repo": "https://github.com/team-alembic/ash_authentication",
              "vendor": "team-alembic",
              "versions": [
                {
                  "lessThan": "4.15.0",
                  "status": "affected",
                  "version": "0.6.0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "5.0.0-rc.14",
                  "status": "affected",
                  "version": "5.0.0-rc.0",
                  "versionType": "semver"
                }
              ]
            },
            {
              "collectionURL": "https://github.com",
              "cpes": [
                "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
              ],
              "defaultStatus": "unaffected",
              "modules": [
                "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027"
              ],
              "packageName": "team-alembic/ash_authentication",
              "packageURL": "pkg:github/team-alembic/ash_authentication",
              "product": "ash_authentication",
              "programFiles": [
                "lib/ash_authentication/strategies/oauth2/plug.ex"
              ],
              "programRoutines": [
                {
                  "name": "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027:callback/2"
                },
                {
                  "name": "\u0027Elixir.AshAuthentication.Strategy.OAuth2.Plug\u0027:request/2"
                }
              ],
              "repo": "https://github.com/team-alembic/ash_authentication",
              "vendor": "team-alembic",
              "versions": [
                {
                  "changes": [
                    {
                      "at": "bd4352303bc9d72d007f6818775267585a4bcc2f",
                      "status": "unaffected"
                    },
                    {
                      "at": "d7f939cd02bd618bcaa304631846fa75ffc419d7",
                      "status": "unaffected"
                    }
                  ],
                  "lessThan": "*",
                  "status": "affected",
                  "version": "c5f589058e04239263f50a1430eb17ea6d5dd1a2",
                  "versionType": "git"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "4.15.0",
                      "versionStartIncluding": "0.6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.0.0-rc.14",
                      "versionStartIncluding": "5.0.0-rc.0",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ],
              "operator": "AND"
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "Peter Ullrich"
            },
            {
              "lang": "en",
              "type": "analyst",
              "value": "Jonatan M\u00e4nnchen / EEF"
            },
            {
              "lang": "en",
              "type": "remediation developer",
              "value": "James Harton"
            }
          ],
          "dateAssigned": "2026-09-11T18:16:32.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eInsufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim\u0027s OAuth2 \u003ccode\u003estate\u003c/code\u003e value to replay the callback and sign that victim into an attacker-controlled account.\u003c/p\u003e\n\u003cp\u003e\u003ccode\u003eAshAuthentication.Strategy.OAuth2.Plug.callback/2\u003c/code\u003e clears the stored \u003ccode\u003esession_params\u003c/code\u003e through a rebinding step inside its \u003ccode\u003ewith\u003c/code\u003e chain, \u003ccode\u003econn \u0026lt;- delete_session(conn, session_key)\u003c/code\u003e. Elixir evaluates the \u003ccode\u003eelse\u003c/code\u003e block in the scope enclosing the \u003ccode\u003ewith\u003c/code\u003e, so every failure path (the provider returning \u003ccode\u003e?error=access_denied\u003c/code\u003e, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches \u003ccode\u003estore_authentication_result/2\u003c/code\u003e holding the original connection and the session entry is never removed. The value the module\u0027s own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry.\u003c/p\u003e\n\u003cp\u003eThis issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.\u003c/p\u003e"
                },
                {
                  "base64": false,
                  "type": "text/markdown",
                  "value": "Insufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim\u0027s OAuth2 `state` value to replay the callback and sign that victim into an attacker-controlled account.\n\n`AshAuthentication.Strategy.OAuth2.Plug.callback/2` clears the stored `session_params` through a rebinding step inside its `with` chain, `conn \u003c- delete_session(conn, session_key)`. Elixir evaluates the `else` block in the scope enclosing the `with`, so every failure path (the provider returning `?error=access_denied`, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches `store_authentication_result/2` holding the original connection and the session entry is never removed. The value the module\u0027s own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry.\n\nThis issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
                }
              ],
              "value": "Insufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim\u0027s OAuth2 state value to replay the callback and sign that victim into an attacker-controlled account.\n\nAshAuthentication.Strategy.OAuth2.Plug.callback/2 clears the stored session_params through a rebinding step inside its with chain, conn \u003c- delete_session(conn, session_key). Elixir evaluates the else block in the scope enclosing the with, so every failure path (the provider returning ?error=access_denied, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches store_authentication_result/2 holding the original connection and the session entry is never removed. The value the module\u0027s own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry.\n\nThis issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
            }
          ],
          "impacts": [
            {
              "capecId": "CAPEC-60",
              "descriptions": [
                {
                  "lang": "en",
                  "value": "CAPEC-60 Reusing Session IDs (aka Session Replay)"
                }
              ]
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "HIGH",
                "attackRequirements": "PRESENT",
                "attackVector": "NETWORK",
                "baseScore": 2.3,
                "baseSeverity": "LOW",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "PASSIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "LOW",
                "vulnIntegrityImpact": "LOW",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-613",
                  "description": "CWE-613 Insufficient Session Expiration",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-09-17T13:09:06.571Z",
            "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
            "shortName": "EEF"
          },
          "references": [
            {
              "tags": [
                "vendor-advisory",
                "related"
              ],
              "url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-3vcj-gxx8-3p44"
            },
            {
              "name": "EEF CNA record for CVE-2026-81637",
              "tags": [
                "related"
              ],
              "url": "https://cna.erlef.org/cves/CVE-2026-81637.html"
            },
            {
              "name": "OSV record EEF-CVE-2026-81637",
              "tags": [
                "related"
              ],
              "url": "https://osv.dev/vulnerability/EEF-CVE-2026-81637"
            },
            {
              "name": "Introducing commit c5f5890 in team-alembic/ash_authentication",
              "tags": [
                "related"
              ],
              "url": "https://github.com/team-alembic/ash_authentication/commit/c5f589058e04239263f50a1430eb17ea6d5dd1a2"
            },
            {
              "name": "Fix commit bd43523 in team-alembic/ash_authentication",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/team-alembic/ash_authentication/commit/bd4352303bc9d72d007f6818775267585a4bcc2f"
            },
            {
              "name": "Fix commit d7f939c in team-alembic/ash_authentication",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/team-alembic/ash_authentication/commit/d7f939cd02bd618bcaa304631846fa75ffc419d7"
            }
          ],
          "source": {
            "discovery": "INTERNAL"
          },
          "title": "Replayable OAuth2 CSRF state retained after a failed callback in AshAuthentication"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "assignerShortName": "EEF",
        "cveId": "CVE-2026-81637",
        "datePublished": "2026-09-17T13:09:06.571Z",
        "dateReserved": "2026-09-11T18:15:01.808Z",
        "dateUpdated": "2026-09-17T18:26:58.389Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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