CVE-2026-53666
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.
- Record
CVE-2026-53666- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-470
- Updated
- 2026-11-02
EUVDEUVD-2026-49628
React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.
- Record
EUVD-2026-49628- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-337j-9hxr-rhxg
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
If application code allows attacker supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for attacker to trigger unexpected constructor execution on the client which would trigger outbound network traffic. This is only possible with very specific (and unlikely) application layer code.
[!NOTE] This does not impact your application if you are using Declarative Mode. This only impacts Framework Mode and Data Mode applications doing manual SSR/hydration
- Record
GHSA-337j-9hxr-rhxg- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-470
- Updated
- 2026-11-02
NVD
React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.
- Record
CVE-2026-53666- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-470
- Updated
- 2026-11-02
OSV
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.
- Record
CVE-2026-53666- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-470
- Updated
- 2026-11-02
OSVGHSA-337j-9hxr-rhxg
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
If application code allows attacker supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for attacker to trigger unexpected constructor execution on the client which would trigger outbound network traffic. This is only possible with very specific (and unlikely) application layer code.
[!NOTE] This does not impact your application if you are using Declarative Mode. This only impacts Framework Mode and Data Mode applications doing manual SSR/hydration
- Record
GHSA-337j-9hxr-rhxg- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-470
- Updated
- 2026-11-02
Show 21 moreShow less
OSVCLSA-2026-1784856210No score
TuxCare security update for react-router (2 CVEs)
TuxCare rebuilt react-router to address 2 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1784856210- Updated
- 2026-11-10
OSVCLSA-2026-1787668126No score
TuxCare security update for 2 packages (3 CVEs)
TuxCare rebuilt 2 packages to address 3 CVEs. Fixed in 6.30.4-tuxcare.1.
- Record
CLSA-2026-1787668126- Updated
- 2026-11-02
OSVCLSA-2026-1789159895No score
TuxCare security update for 2 packages (1 CVE)
TuxCare rebuilt 2 packages to address 1 CVE. Fixed in 6.30.3-tuxcare.2.
- Record
CLSA-2026-1789159895- Updated
- 2026-11-02
OSVCLSA-2026-1791465168No score
TuxCare security update for react-router (4 CVEs)
TuxCare rebuilt react-router to address 4 CVEs. Fixed in 7.15.0-tuxcare.1.
- Record
CLSA-2026-1791465168- Updated
- 2026-11-02
OSVCLSA-2026-1792191744No score
TuxCare security update for react-router (4 CVEs)
TuxCare rebuilt react-router to address 4 CVEs. Fixed in 7.14.2-tuxcare.1.
- Record
CLSA-2026-1792191744- Updated
- 2026-11-02
OSVCLSA-2026-1792253402No score
TuxCare security update for react-router-dom (4 CVEs)
TuxCare rebuilt react-router-dom to address 4 CVEs. Fixed in 7.15.0-tuxcare.1.
- Record
CLSA-2026-1792253402- Updated
- 2026-11-02
OSVCLSA-2026-1792253408No score
TuxCare security update for react-router-dom (1 CVE)
TuxCare rebuilt react-router-dom to address 1 CVE. Fixed in 6.30.3-tuxcare.2.
- Record
CLSA-2026-1792253408- Updated
- 2026-11-02
OSVCLSA-2026-1792253416No score
TuxCare security update for react-router-dom (4 CVEs)
TuxCare rebuilt react-router-dom to address 4 CVEs. Fixed in 7.14.2-tuxcare.1.
- Record
CLSA-2026-1792253416- Updated
- 2026-11-02
OSVCLSA-2026-1792269434No score
TuxCare security update for react-router-native (1 CVE)
TuxCare rebuilt react-router-native to address 1 CVE. Fixed in 6.30.3-tuxcare.2.
- Record
CLSA-2026-1792269434- Updated
- 2026-11-02
OSVCLSA-2026-1792419111No score
TuxCare security update for @react-router/architect (3 CVEs)
TuxCare rebuilt @react-router/architect to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792419111- Updated
- 2026-11-02
OSVCLSA-2026-1792419188No score
TuxCare security update for @react-router/cloudflare (3 CVEs)
TuxCare rebuilt @react-router/cloudflare to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792419188- Updated
- 2026-11-02
OSVCLSA-2026-1792419267No score
TuxCare security update for @react-router/express (3 CVEs)
TuxCare rebuilt @react-router/express to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792419267- Updated
- 2026-11-02
OSVCLSA-2026-1792421941No score
TuxCare security update for @react-router/remix-routes-option-adapter (3 CVEs)
TuxCare rebuilt @react-router/remix-routes-option-adapter to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792421941- Updated
- 2026-11-02
OSVCLSA-2026-1792424730No score
TuxCare security update for @react-router/dev (3 CVEs)
TuxCare rebuilt @react-router/dev to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792424730- Updated
- 2026-11-02
OSVCLSA-2026-1792425405No score
TuxCare security update for @react-router/fs-routes (3 CVEs)
TuxCare rebuilt @react-router/fs-routes to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792425405- Updated
- 2026-11-02
OSVCLSA-2026-1792428107No score
TuxCare security update for @react-router/serve (3 CVEs)
TuxCare rebuilt @react-router/serve to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792428107- Updated
- 2026-11-02
OSVCLSA-2026-1792430030No score
TuxCare security update for create-react-router (3 CVEs)
TuxCare rebuilt create-react-router to address 3 CVEs. Fixed in 7.5.1-tuxcare.5.
- Record
CLSA-2026-1792430030- Updated
- 2026-11-02
OSVCLSA-2026-1792840526No score
TuxCare security update for @remix-run/router (3 CVEs)
TuxCare rebuilt @remix-run/router to address 3 CVEs. Fixed in 1.23.3-tuxcare.1.
- Record
CLSA-2026-1792840526- Updated
- 2026-11-02
OSVCLSA-2026-1793099986No score
TuxCare security update for react-router (3 CVEs)
TuxCare rebuilt react-router to address 3 CVEs. Fixed in 7.14.1-tuxcare.2.
- Record
CLSA-2026-1793099986- Updated
- 2026-11-06
OSVCLSA-2026-1793102180No score
TuxCare security update for react-router (5 CVEs)
TuxCare rebuilt react-router to address 5 CVEs. Fixed in 7.13.1-tuxcare.2.
- Record
CLSA-2026-1793102180- Updated
- 2026-11-06
OSVROOT-APP-NPM-CVE-2026-53666No score
CVE-2026-53666 in react-router - Patched by Root
Root has patched CVE-2026-53666 in the react-router package for Root:npm. Multiple fixed versions available.
- Record
ROOT-APP-NPM-CVE-2026-53666- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
react-routernpm | 6.4.0 up to 7.18.0 | 7.18.0 |
react-routerTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.27.5.1-tuxcare.37.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
react-routerTuxCare:npm From an advisory covering 3 CVEs | 6.30.4-tuxcare.0 up to 6.30.4-tuxcare.1, plus listed versions 6.30.4 | 6.30.4-tuxcare.1 |
react-router-dom-v5-compatTuxCare:npm From an advisory covering 3 CVEs | 6.30.4-tuxcare.0 up to 6.30.4-tuxcare.1, plus listed versions 6.30.4 | 6.30.4-tuxcare.1 |
react-routerTuxCare:npm | 6.30.3-tuxcare.0 up to 6.30.3-tuxcare.2, plus listed versions 6.30.36.30.3-tuxcare.1 | 6.30.3-tuxcare.2 |
react-router-dom-v5-compatTuxCare:npm | 6.30.3-tuxcare.0 up to 6.30.3-tuxcare.2, plus listed versions 6.30.36.30.3-tuxcare.1 | 6.30.3-tuxcare.2 |
react-routerTuxCare:npm From an advisory covering 4 CVEs | 7.15.0-tuxcare.0 up to 7.15.0-tuxcare.1, plus listed versions 7.15.0 | 7.15.0-tuxcare.1 |
react-routerTuxCare:npm From an advisory covering 4 CVEs | 7.14.2-tuxcare.0 up to 7.14.2-tuxcare.1, plus listed versions 7.14.2 | 7.14.2-tuxcare.1 |
react-router-domTuxCare:npm From an advisory covering 4 CVEs | 7.15.0-tuxcare.0 up to 7.15.0-tuxcare.1, plus listed versions 7.15.0 | 7.15.0-tuxcare.1 |
react-router-domTuxCare:npm | 6.30.3-tuxcare.0 up to 6.30.3-tuxcare.2, plus listed versions 6.30.36.30.3-tuxcare.1 | 6.30.3-tuxcare.2 |
Show 15 moreShow less
| Package | Affected | Fixed |
|---|---|---|
react-router-domTuxCare:npm From an advisory covering 4 CVEs | 7.14.2-tuxcare.0 up to 7.14.2-tuxcare.1, plus listed versions 7.14.2 | 7.14.2-tuxcare.1 |
react-router-nativeTuxCare:npm | 6.30.3-tuxcare.0 up to 6.30.3-tuxcare.2, plus listed versions 6.30.36.30.3-tuxcare.1 | 6.30.3-tuxcare.2 |
@react-router/architectTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/cloudflareTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/expressTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/remix-routes-option-adapterTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/devTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/fs-routesTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@react-router/serveTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
create-react-routerTuxCare:npm From an advisory covering 3 CVEs | 7.5.1-tuxcare.0 up to 7.5.1-tuxcare.5, plus listed versions 7.5.17.5.1-tuxcare.17.5.1-tuxcare.4 | 7.5.1-tuxcare.5 |
@remix-run/routerTuxCare:npm From an advisory covering 3 CVEs | 1.23.3-tuxcare.0 up to 1.23.3-tuxcare.1, plus listed versions 1.23.3 | 1.23.3-tuxcare.1 |
react-routerTuxCare:npm From an advisory covering 2 CVEs | 7.14.1-tuxcare.0 up to 7.14.1-tuxcare.2, plus listed versions 7.14.17.14.1-tuxcare.1 | 7.14.1-tuxcare.2 |
react-routerTuxCare:npm From an advisory covering 5 CVEs | 7.13.1-tuxcare.0 up to 7.13.1-tuxcare.2, plus listed versions 7.13.17.13.1-tuxcare.1 | 7.13.1-tuxcare.2 |
react-routerRoot:npm | before 7.18.0-aikido.1 | 7.18.0-aikido.1 |
@rootio/react-routerRoot:npm | before 7.18.0-root.io.1 | 7.18.0-root.io.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases | OSV | |
| affected, aliases | ||
| affected | OSV | |
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-53666 is a medium vulnerability (CVSS 6.1) in @tanstack React-router, published July 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in react-router 7.18.0.
References
github.com/remix-run/react-router/security/advisories/GHSA-337j-9hxr-rhxg
nvd.nist.gov/vuln/detail/CVE-2026-53666