Fastify Fixes Proxy Boundaries, Session Validation, and Denial of Service
Tech GuruQuick Answer
Seven project advisories address proxy path restrictions, session-signature handling, delayed multipart consumption, CORS onSend and timed streaming responses. Upgrade the affected dependencies, test security boundaries and retain deployed-version evidence.
Confirm Scope And Apply The Supported Remediation
What to do now: Record deployed Fastify/plugin versions, proxy prefix and rewritePrefix settings, upstream URL parsing, cookie signing and encryption keys, multipart consumers, CORS hooks and handlerTimeout. Match the documented versions, enabled features and attack prerequisites to the deployment before assigning applicability. Upgrade the affected packages to the listed versions. The http-proxy 11.6.6 target covers both proxy advisories. For temporary measures, use an allowed CORS hook, disable handlerTimeout where appropriate, and rotate the session encryption key when retiring sessions. Test upstream path isolation, session invalidation, malformed uploads, preflight requests and streaming timeout behavior; retain lockfiles, deployed builds and regression results.
Last verified: 2026-11-02 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | Fastify and @fastify/http-proxy, reply-from, secure-session, multipart and cors plugins |
|---|---|
| Advisory | GHSA-8c3j-mm64-257c / GHSA-h3vp-4jfr-v364 / GHSA-hr26-gmr2-pwcv / GHSA-5849-5m6q-9632 / GHSA-vp2r-3vgv-32g9 / GHSA-4cgq-x5f7-r8jv / GHSA-3qgw-9275-xf8w |
| CVEs | CVE-2026-117518, CVE-2026-117531, CVE-2026-117549, CVE-2026-120213, CVE-2026-120214, CVE-2026-120215, CVE-2026-120216 |
| Authoritative release date | 2026-11-02 10:49:36 UTC |
| Authority revision date | No separate later revision date is displayed in the captured project advisories. |
| Affected versions | Issue-specific package ranges and configurations listed below; confirm feature use before assigning applicability. |
| Fixed version | fastify 5.12.8; @fastify/http-proxy 11.6.6; @fastify/reply-from 12.8.1; @fastify/secure-session 8.4.2; @fastify/multipart 10.1.7; @fastify/cors 11.4.0 |
| CVSS base score | 3.7-9.1 (CVSS v3.1; CVE-specific) |
| CVSS severity | Low to Critical |
| Exploitation status | The cited authority does not state that this issue is being maliciously exploited.; no exploitation claim is inferred. |
Authority-Specific Scope And Version Evidence
| GHSA-8c3j-mm64-257c / CVE-2026-120215 | fastify-cors: affected >= 8.2.0, < 11.4.0 Patched versions 11.4.0. CVSS v3.1 3.7; Low. Published 2026-11-02T08:50:58Z. |
|---|---|
| GHSA-h3vp-4jfr-v364 / CVE-2026-120213 | fastify-http-proxy: affected >= 9.0.0, < 11.6.6 Patched versions 11.6.6. CVSS v3.1 9.1; Critical. Published 2026-11-02T08:55:12Z. |
| GHSA-hr26-gmr2-pwcv / CVE-2026-120214 | fastify-http-proxy: affected >= 11.6.0, <= 11.6.2 Patched versions 11.6.3. CVSS v3.1 5.9; Moderate. Published 2026-11-02T08:53:01Z. |
| GHSA-5849-5m6q-9632 / CVE-2026-117531 | fastify-multipart: affected >= 5.3.0, < 10.1.7 Patched versions 10.1.7. CVSS v3.1 5.9; Moderate. Published 2026-11-02T09:13:20Z. |
| GHSA-vp2r-3vgv-32g9 / CVE-2026-117518 | fastify-reply-from: affected < 12.8.1 Patched versions 12.8.1. CVSS v3.1 8.2; High. Published 2026-11-02T09:02:11Z. |
| GHSA-4cgq-x5f7-r8jv / CVE-2026-117549 | fastify-secure-session: affected >= 7.5.0, < 8.4.2 Patched versions 8.4.2. CVSS v3.1 4.2; Moderate. Published 2026-11-02T09:08:42Z. |
| GHSA-3qgw-9275-xf8w / CVE-2026-120216 | fastify: affected >= 5.8.0, < 5.12.8 Patched versions 5.12.8. CVSS v3.1 5.9; Moderate. Published 2026-11-02T10:49:36Z. |
What Changed
Seven project advisories address proxy path restrictions, session-signature handling, delayed multipart consumption, CORS onSend and timed streaming responses.
What To Validate Now
- Inventory. Record deployed Fastify/plugin versions, proxy prefix and rewritePrefix settings, upstream URL parsing, cookie signing and encryption keys, multipart consumers, CORS hooks and handlerTimeout.
- Establish applicability. Match the documented versions, enabled features and attack prerequisites to the deployment before assigning applicability.
- Remediate. Upgrade the affected packages to the listed versions. The http-proxy 11.6.6 target covers both proxy advisories. For temporary measures, use an allowed CORS hook, disable handlerTimeout where appropriate, and rotate the session encryption key when retiring sessions.
- Validate. Test upstream path isolation, session invalidation, malformed uploads, preflight requests and streaming timeout behavior; retain lockfiles, deployed builds and regression results.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Do not use cookie-signing-key rotation alone to retire secure-session cookies. The CORS update rejects onSend registration; assess configuration changes before rollout. Several proxy and upload issues have no project-supported workaround.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
- GHSA-8c3j-mm64-257c
- GHSA-h3vp-4jfr-v364
- GHSA-hr26-gmr2-pwcv
- GHSA-5849-5m6q-9632
- GHSA-vp2r-3vgv-32g9
- GHSA-4cgq-x5f7-r8jv
- GHSA-3qgw-9275-xf8w
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
