vulnerability / NVI-00011991 / Revision 3
FrankenPHP: Cross-request PHP session ID leak in worker mode when the session extension is a shared module
GitHub lists this reviewed advisory for github.com/dunglas/frankenphp. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.7 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
7.7 HIGH (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.293%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.2186. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/dunglas/frankenphp
source listed<= 1.12.4
## Summary In worker mode under concurrency, FrankenPHP can hand a PHP session id from one request to another when PHP's `session` extension is loaded as a shared module instead of being statically linked into the FrankenPHP binary. A request presenting `Cookie: session=A` can have `session_id()` resolve to `B` (a different concurrent client's id) or to a stale id from a previous request served by the same worker thread. ## Impact - **Security:** cross-user session exposure / session hijacking in worker mode. Same impact class as CVE-2026-24894. - **Functional:** users are intermittently logged out; their cookie's session is ignored and they receive a foreign or empty session. ## Affected / not affected Exposure is determined by how the `session` extension is linked in the PHP build FrankenPHP is compiled against, **not** by the FrankenPHP release: - **Affected:** any build where the `session` extension is not visible to FrankenPHP at compile time, i.e. loaded as a shared / out-of-tree module (`extension=session` in an ini). This includes the RPM and Debian packages and other packaged `php-zts` distributions that ship `session` as a shared extension under `conf.d`. - **Not affec
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-v3ph-cgqh-r8p5 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-82416 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-82416 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.