{"id":"CVE-2026-82416","kind":"vulnerability","aliases":["CVE-2026-82416","GHSA-v3ph-cgqh-r8p5","GO-2026-6797"],"related":[],"title":"FrankenPHP: Cross-request PHP session ID leak in worker mode when the session extension is a shared module in github.com/dunglas/frankenphp","description":"FrankenPHP is a modern application server for PHP. Prior to 1.12.5, FrankenPHP worker mode can retain PHP session state between requests when the session extension is loaded as a shared module and is unavailable through HAVE_PHP_SESSION at compile time. In this build configuration, frankenphp_reset_session_state() is compiled out, PS(id) can survive a request boundary, and a subsequent session_start() can ignore the new request's cookie because an identifier is already present. Under concurrent requests, session_id() can therefore return another client's identifier or a stale identifier from a previous request on the same worker thread, causing cross-user session exposure, possible session hijacking, and intermittent logout behavior. Builds with the session extension statically linked, including the official static binaries and Docker images, are not affected. This issue is fixed in version 1.12.5.","summary":"FrankenPHP worker mode can keep a PHP session ID from one request and reuse it in a later request on the same worker, when the session extension is built as a shared module. An attacker can then read another user's session or hijack it.","severity":"high","cvss":7.7,"epss":0.00227,"exploited":false,"exploited_at":null,"products":[{"name":"github.com/dunglas/frankenphp","fixed":["1.12.5"],"affected":"< 1.12.5","ecosystem":"go"}],"ecosystems":["go"],"tags":["frankenphp","go","php","runtime","self-hosted","worker-mode"],"not_affected_if":["official-docker-image","session-extension-statically-linked","static-build","worker-mode-disabled"],"how_to_check":"Check whether your FrankenPHP build loads the session extension as a shared module (not compiled in), for example with php -m or by checking how the binary was built; official static binaries and Docker images are not affected.\nCheck the installed version with frankenphp version or your go.mod entry for github.com/dunglas/frankenphp; affected if below 1.12.5.","fix":"Upgrade github.com/dunglas/frankenphp to 1.12.5 or later.\nIf you cannot upgrade, switch to a static build with the session extension linked in, such as the official binaries or Docker images.","status":"open","published_at":"2026-10-13T17:17:47+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","triaged_at":"2026-10-23T19:52:56+00:00","updated_at":"2026-10-23T19:52:56+00:00","category":"runtime","confidence":0.8,"triage":{"at":"2026-10-23T19:52:56Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade github.com/dunglas/frankenphp to 1.12.5 or later.\nIf you cannot upgrade, switch to a static build with the session extension linked in, such as the official binaries or Docker images.","summary":"FrankenPHP worker mode can keep a PHP session ID from one request and reuse it in a later request on the same worker, when the session extension is built as a shared module. An attacker can then read another user's session or hijack it.","category":"runtime","who_cares":["frankenphp","php","worker-mode","self-hosted","go"],"confidence":0.8,"analyst_note":"","how_to_check":"Check whether your FrankenPHP build loads the session extension as a shared module (not compiled in), for example with php -m or by checking how the binary was built; official static binaries and Docker images are not affected.\nCheck the installed version with frankenphp version or your go.mod entry for github.com/dunglas/frankenphp; affected if below 1.12.5.","needs_analyst":false,"not_affected_if":["static-build","official-docker-image","worker-mode-disabled","session-extension-statically-linked"],"severity_if_unknown":"high"},"cost_usd":0.000431,"input_tokens":2343,"output_tokens":394,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':25A,33A,36A '-6797':34A '-82416':26A,37A '/dunglas/frankenphp':23A,40A '1.12.5':105C,234C 'affect':227C 'alreadi':170C 'anoth':89B,180C 'applic':99C 'attack':85B 'behavior':209C 'binari':221C 'boundari':153C 'build':138C,210C 'built':79B 'caus':197C 'cgqh':30A 'client':181C 'compil':134C,145C 'concurr':173C 'configur':139C 'cooki':165C 'cross':3A,199C 'cross-request':2A 'cross-us':198C 'cve':24A,35A 'docker':223C 'exposur':202C 'extens':15A,77B,119C,214C 'fix':231C 'frankenphp':1A,41B,51B,95C,106C,140C 'ghsa':28A 'ghsa-v3ph-cgqh-r8p5':27A 'github.com':22A,39A 'github.com/dunglas/frankenphp':21A,38A 'go':32A,42B 'hijack':94B,205C 'host':47B 'id':7A,59B,148C,176C 'identifi':168C,183C,187C 'ignor':160C 'imag':224C 'includ':217C 'intermitt':207C 'issu':229C 'keep':55B 'later':68B 'leak':8A 'link':216C 'load':121C 'logout':208C 'mode':11A,50B,53B,108C 'modern':98C 'modul':19A,83B,125C 'new':162C 'offici':219C 'one':61B 'php':5A,43B,57B,102C,111C,131C 'possibl':203C 'present':171C 'previous':190C 'prior':103C 'ps':147C 'r8p5':31A 'read':88B 'request':4A,62B,69B,115C,152C,163C,174C,191C 'reset':141C 'retain':110C 'return':179C 'reus':64B 'runtim':44B 'self':46B 'self-host':45B 'server':100C 'session':6A,14A,58B,76B,92B,112C,118C,132C,142C,157C,175C,201C,204C,213C 'share':18A,82B,124C 'stale':186C 'start':158C 'state':113C,143C 'static':215C,220C 'subsequ':156C 'surviv':150C 'therefor':178C 'thread':196C 'time':135C 'unavail':128C 'user':90B,200C 'v3ph':29A 'version':233C 'worker':10A,49B,52B,73B,107C,195C 'worker-mod':48B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-13T17:17:47+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"govuln","external_id":"GO-2026-6797","url":"https://pkg.go.dev/vuln/GO-2026-6797","severity":null,"published_at":"2026-10-19T21:08:35+00:00","modified_at":"2026-10-19T21:08:35+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","fetched_at":"2026-10-23T19:13:08+00:00","note":null},{"source":"epss","external_id":"CVE-2026-82416","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-82416","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-82416","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-82416","severity":null,"published_at":"2026-10-13T17:17:47+00:00","modified_at":"2026-10-16T20:04:29+00:00","first_seen_at":"2026-10-23T19:35:23+00:00","fetched_at":"2026-10-23T19:35:23+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}