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Fencer Vulns
low 3.7

CVE-2026-33877 json

ApostropheCMS: User Enumeration via Timing Side Channel in Password Reset Endpoint

published 2026-04-15 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-23015 , GHSA-mj7r-x3h3-7rmr

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm apostrophe 4.29.0
  • apostrophecms apostrophecms 4.29.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-mj7r-x3h3-7rmr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm apostrophe
<4.29.0
4.29.0

Affected products

  • apostrophecms apostrophe

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.