diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7891e9d2ea..108b138dbb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,8 +9,10 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 * [`jsx-key`]: prevent false "missing array key" warning ([#3215][] @ljharb)
 * [`jsx-indent`]: avoid checking returns sans jsx ([#3218][] @ljharb)
 * [`jsx-key`]: avoid a crash ([#3220][] @ljharb)
+* version settings: avoid a crash with an invalid version ([#3219][] @ljharb)
 
 [#3220]: https://github.com/yannickcr/eslint-plugin-react/issues/3220
+[#3219]: https://github.com/yannickcr/eslint-plugin-react/issues/3219
 [#3218]: https://github.com/yannickcr/eslint-plugin-react/issues/3218
 [#3215]: https://github.com/yannickcr/eslint-plugin-react/issues/3215
 
diff --git a/lib/util/version.js b/lib/util/version.js
index c762e02bd0..975b76d5fe 100644
--- a/lib/util/version.js
+++ b/lib/util/version.js
@@ -70,8 +70,10 @@ function detectReactVersion(context) {
   }
 }
 
+const defaultVersion = '999.999.999';
+
 function getReactVersionFromContext(context) {
-  let confVer = '999.999.999';
+  let confVer = defaultVersion;
   // .eslintrc shared settings (https://eslint.org/docs/user-guide/configuring#adding-shared-settings)
   if (context.settings && context.settings.react && context.settings.react.version) {
     let settingsVersion = context.settings.react.version;
@@ -89,7 +91,11 @@ function getReactVersionFromContext(context) {
     warnedForMissingVersion = true;
   }
   confVer = /^[0-9]+\.[0-9]+$/.test(confVer) ? `${confVer}.0` : confVer;
-  return semver.coerce(confVer.split('.').map((part) => Number(part)).join('.')).version;
+  const result = semver.coerce(confVer.split('.').map((part) => Number(part)).join('.'));
+  if (!result) {
+    error(`Warning: React version specified in eslint-plugin-react-settings must be a valid semver version, or "detect"; got “${confVer}”`);
+  }
+  return result ? result.version : defaultVersion;
 }
 
 // TODO, semver-major: remove context fallback
@@ -111,7 +117,7 @@ function detectFlowVersion(context) {
 }
 
 function getFlowVersionFromContext(context) {
-  let confVer = '999.999.999';
+  let confVer = defaultVersion;
   // .eslintrc shared settings (https://eslint.org/docs/user-guide/configuring#adding-shared-settings)
   if (context.settings.react && context.settings.react.flowVersion) {
     let flowVersion = context.settings.react.flowVersion;
@@ -127,7 +133,11 @@ function getFlowVersionFromContext(context) {
     throw 'Could not retrieve flowVersion from settings'; // eslint-disable-line no-throw-literal
   }
   confVer = /^[0-9]+\.[0-9]+$/.test(confVer) ? `${confVer}.0` : confVer;
-  return semver.coerce(confVer.split('.').map((part) => Number(part)).join('.')).version;
+  const result = semver.coerce(confVer.split('.').map((part) => Number(part)).join('.'));
+  if (!result) {
+    error(`Warning: Flow version specified in eslint-plugin-react-settings must be a valid semver version, or "detect"; got “${confVer}”`);
+  }
+  return result ? result.version : defaultVersion;
 }
 
 function test(semverRange, confVer) {
diff --git a/tests/util/version.js b/tests/util/version.js
index a0bfe06252..ad9bd4585c 100644
--- a/tests/util/version.js
+++ b/tests/util/version.js
@@ -103,6 +103,7 @@ describe('Version', () => {
 
   describe('string version', () => {
     const context = { settings: { react: { version: '15.0', flowVersion: '1.2' } } };
+    const invalidContext = { settings: { react: { version: 'latest', flowVersion: 'not semver' } } };
 
     it('works with react', () => {
       assert.equal(versionUtil.testReactVersion(context, '>= 0.14.0'), true);
@@ -115,6 +116,20 @@ describe('Version', () => {
       assert.equal(versionUtil.testFlowVersion(context, '>= 1.2.0'), true);
       assert.equal(versionUtil.testFlowVersion(context, '>= 1.3.0'), false);
     });
+
+    it('fails nicely with an invalid react version', () => {
+      assert.equal(versionUtil.testReactVersion(invalidContext, '>= 15.0'), true);
+      expectedErrorArgs = [
+        ['Warning: React version specified in eslint-plugin-react-settings must be a valid semver version, or "detect"; got “latest”'],
+      ];
+    });
+
+    it('fails nicely with an invalid flow version', () => {
+      assert.equal(versionUtil.testFlowVersion(invalidContext, '>= 1.0'), true);
+      expectedErrorArgs = [
+        ['Warning: Flow version specified in eslint-plugin-react-settings must be a valid semver version, or "detect"; got “not semver”'],
+      ];
+    });
   });
 
   describe('non-string version', () => {